Move the in-process WebGL implementation from the WebKit to the...

webkit/gpu/webgraphicscontext3d_in_process_impl.cc

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "webkit/gpu/webgraphicscontext3d_in_process_impl.h"
+
+#include <string.h>
+
+#include <algorithm>
+#include <string>
+
+#include "app/gfx/gl/gl_bindings.h"
+#include "app/gfx/gl/gl_context.h"
+#include "app/gfx/gl/gl_implementation.h"
+#include "base/logging.h"
+#include "third_party/WebKit/WebKit/chromium/public/WebString.h"
+#include "third_party/WebKit/WebKit/chromium/public/WebView.h"
+
+using WebKit::WebGLId;
+using WebKit::WebGraphicsContext3D;
+using WebKit::WebString;
+using WebKit::WebView;
+
+namespace webkit_gpu {
+
+enum {
+  MAX_VERTEX_UNIFORM_VECTORS = 0x8DFB,
+  MAX_VARYING_VECTORS = 0x8DFC,
+  MAX_FRAGMENT_UNIFORM_VECTORS = 0x8DFD
+};
+
+WebGraphicsContext3DInProcessImpl::
+    VertexAttribPointerState::VertexAttribPointerState()
+    : enabled(false),
+      buffer(0),
+      indx(0),
+      size(0),
+      type(0),
+      normalized(false),
+      stride(0),
+      offset(0) {
+}
+
+WebGraphicsContext3DInProcessImpl::WebGraphicsContext3DInProcessImpl()
+    : initialized_(false),
+      render_directly_to_web_view_(false),
+      is_gles2_(false),
+      have_ext_framebuffer_object_(false),
+      have_ext_framebuffer_multisample_(false),
+      have_angle_framebuffer_multisample_(false),
+      texture_(0),
+      fbo_(0),
+      depth_stencil_buffer_(0),
+      cached_width_(0),
+      cached_height_(0),
+      multisample_fbo_(0),
+      multisample_depth_stencil_buffer_(0),
+      multisample_color_buffer_(0),
+      bound_fbo_(0),
+      bound_texture_(0),
+      copy_texture_to_parent_texture_fbo_(0),
+      bound_array_buffer_(0),
+#ifdef FLIP_FRAMEBUFFER_VERTICALLY
+      scanline_(0),
+#endif
+      fragment_compiler_(0),
+      vertex_compiler_(0) {
+}
+
+WebGraphicsContext3DInProcessImpl::~WebGraphicsContext3DInProcessImpl() {
+  if (initialized_) {

[darin (slow to review), 2011/01/11 19:32:51]

nit: recommend returning early if !initialized_ to reduce indentation

+    makeContextCurrent();
+
+    if (attributes_.antialias) {
+      glDeleteRenderbuffersEXT(1, &multisample_color_buffer_);
+      if (attributes_.depth || attributes_.stencil)
+        glDeleteRenderbuffersEXT(1, &multisample_depth_stencil_buffer_);
+      glDeleteFramebuffersEXT(1, &multisample_fbo_);
+    } else {
+      if (attributes_.depth || attributes_.stencil)
+        glDeleteRenderbuffersEXT(1, &depth_stencil_buffer_);
+    }
+    glDeleteTextures(1, &texture_);
+    glDeleteFramebuffersEXT(1, &copy_texture_to_parent_texture_fbo_);
+#ifdef FLIP_FRAMEBUFFER_VERTICALLY
+    if (scanline_)
+      delete[] scanline_;
+#endif
+    glDeleteFramebuffersEXT(1, &fbo_);
+
+    gl_context_->Destroy();
+
+    for (ShaderSourceMap::iterator ii = shader_source_map_.begin();
+         ii != shader_source_map_.end(); ++ii) {
+      if (ii->second)
+        delete ii->second;
+    }
+    AngleDestroyCompilers();
+  }
+}
+
+bool WebGraphicsContext3DInProcessImpl::initialize(
+    WebGraphicsContext3D::Attributes attributes,
+    WebView* webView,
+    bool render_directly_to_web_view) {
+  if (!gfx::GLContext::InitializeOneOff())
+    return false;
+
+  render_directly_to_web_view_ = render_directly_to_web_view;
+  gfx::GLContext* share_context = 0;
+
+  if (!render_directly_to_web_view) {
+    // Pick up the compositor's context to share resources with.
+    WebGraphicsContext3D* view_context = webView->graphicsContext3D();
+    if (view_context) {
+      WebGraphicsContext3DInProcessImpl* contextImpl =
+          static_cast<WebGraphicsContext3DInProcessImpl*>(view_context);
+      share_context = contextImpl->gl_context_.get();
+    } else {
+      // The compositor's context didn't get created
+      // successfully, so conceptually there is no way we can
+      // render successfully to the WebView.
+      render_directly_to_web_view_ = false;
+    }
+  }
+
+  // This implementation always renders offscreen regardless of
+  // whether render_directly_to_web_view is true. Both DumpRenderTree
+  // and test_shell paint first to an intermediate offscreen buffer
+  // and from there to the window, and WebViewImpl::paint already
+  // correctly handles the case where the compositor is active but
+  // the output needs to go to a WebCanvas.
+  gl_context_.reset(gfx::GLContext::CreateOffscreenGLContext(share_context));
+  if (!gl_context_.get())
+    return false;
+
+  attributes_ = attributes;
+
+  // FIXME: for the moment we disable multisampling for the compositor.
+  // It actually works in this implementation, but there are a few
+  // considerations. First, we likely want to reduce the fuzziness in
+  // these tests as much as possible because we want to run pixel tests.
+  // Second, Mesa's multisampling doesn't seem to antialias straight
+  // edges in some CSS 3D samples. Third, we don't have multisampling
+  // support for the compositor in the normal case at the time of this
+  // writing.
+  if (render_directly_to_web_view)
+    attributes_.antialias = false;
+
+  is_gles2_ = gfx::GetGLImplementation() == gfx::kGLImplementationEGLGLES2;
+  const char* extensions =
+      reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
+  have_ext_framebuffer_object_ =
+      strstr(extensions, "GL_EXT_framebuffer_object") != NULL;
+  have_ext_framebuffer_multisample_ =
+      strstr(extensions, "GL_EXT_framebuffer_multisample") != NULL;
+  have_angle_framebuffer_multisample_ =
+      strstr(extensions, "GL_ANGLE_framebuffer_multisample") != NULL;
+
+  ValidateAttributes();
+
+  if (!is_gles2_) {
+    glEnable(GL_VERTEX_PROGRAM_POINT_SIZE);
+    glEnable(GL_POINT_SPRITE);
+  }
+
+  if (!AngleCreateCompilers()) {
+    AngleDestroyCompilers();
+    return false;
+  }
+
+  glGenFramebuffersEXT(1, &copy_texture_to_parent_texture_fbo_);
+
+  initialized_ = true;
+  return true;
+}
+
+void WebGraphicsContext3DInProcessImpl::ValidateAttributes() {
+  const char* extensions =
+      reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
+
+  if (attributes_.stencil) {
+    if (strstr(extensions, "GL_OES_packed_depth_stencil") ||
+        strstr(extensions, "GL_EXT_packed_depth_stencil")) {
+      if (!attributes_.depth) {
+        attributes_.depth = true;
+      }
+    } else {
+      attributes_.stencil = false;
+    }
+  }
+  if (attributes_.antialias) {
+    bool isValidVendor = true;
+#if defined(OS_MACOSX)
+    // Currently in Mac we only turn on antialias if vendor is NVIDIA.
+    const char* vendor = reinterpret_cast<const char*>(glGetString(GL_VENDOR));
+    if (!strstr(vendor, "NVIDIA"))
+      isValidVendor = false;
+#endif
+    if (!(isValidVendor &&
+          (have_ext_framebuffer_multisample_ ||
+           (have_angle_framebuffer_multisample_ &&
+            strstr(extensions, "GL_OES_rgb8_rgba8")))))
+      attributes_.antialias = false;
+
+    // Don't antialias when using Mesa to ensure more reliable testing and
+    // because it doesn't appear to multisample straight lines correctly.
+    const char* renderer =
+        reinterpret_cast<const char*>(glGetString(GL_RENDERER));
+    if (!strncmp(renderer, "Mesa", 4)) {
+      attributes_.antialias = false;
+    }
+  }
+  // FIXME: instead of enforcing premultipliedAlpha = true, implement the
+  // correct behavior when premultipliedAlpha = false is requested.
+  attributes_.premultipliedAlpha = true;
+}
+
+void WebGraphicsContext3DInProcessImpl::ResolveMultisampledFramebuffer(
+    unsigned x, unsigned y, unsigned width, unsigned height) {
+  if (attributes_.antialias) {
+    glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, multisample_fbo_);
+    glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, fbo_);
+    if (have_ext_framebuffer_multisample_) {
+      glBlitFramebufferEXT(x, y,
+                           x + width, y + height,
+                           x, y,
+                           x + width, y + height,
+                           GL_COLOR_BUFFER_BIT, GL_NEAREST);
+    } else {
+      DCHECK(have_angle_framebuffer_multisample_);
+      glBlitFramebufferANGLE(x, y,
+                             x + width, y + height,
+                             x, y,
+                             x + width, y + height,
+                             GL_COLOR_BUFFER_BIT, GL_NEAREST);
+    }
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+  }
+}
+
+bool WebGraphicsContext3DInProcessImpl::makeContextCurrent() {
+  return gl_context_->MakeCurrent();
+}
+
+int WebGraphicsContext3DInProcessImpl::width() {
+  return cached_width_;
+}
+
+int WebGraphicsContext3DInProcessImpl::height() {
+  return cached_height_;
+}
+
+int WebGraphicsContext3DInProcessImpl::sizeInBytes(int type) {
+  switch (type) {
+  case GL_BYTE:
+    return sizeof(GLbyte);
+  case GL_UNSIGNED_BYTE:
+    return sizeof(GLubyte);
+  case GL_SHORT:
+    return sizeof(GLshort);
+  case GL_UNSIGNED_SHORT:
+    return sizeof(GLushort);
+  case GL_INT:
+    return sizeof(GLint);
+  case GL_UNSIGNED_INT:
+    return sizeof(GLuint);
+  case GL_FLOAT:
+    return sizeof(GLfloat);
+  }
+  return 0;
+}
+
+bool WebGraphicsContext3DInProcessImpl::isGLES2Compliant() {
+  return is_gles2_;
+}
+
+unsigned int WebGraphicsContext3DInProcessImpl::getPlatformTextureId() {
+  return texture_;
+}
+
+void WebGraphicsContext3DInProcessImpl::prepareTexture() {
+  if (!render_directly_to_web_view_) {
+    // We need to prepare our rendering results for the compositor.
+    makeContextCurrent();
+    ResolveMultisampledFramebuffer(0, 0, cached_width_, cached_height_);
+  }
+}
+
+namespace {
+
+int CreateTextureObject(GLenum target) {
+  GLuint texture = 0;
+  glGenTextures(1, &texture);
+  glBindTexture(target, texture);
+  glTexParameterf(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameterf(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  return texture;
+}
+
+}  // anonymous namespace
+
+void WebGraphicsContext3DInProcessImpl::reshape(int width, int height) {
+  cached_width_ = width;
+  cached_height_ = height;
+  makeContextCurrent();
+
+  GLenum target = GL_TEXTURE_2D;
+
+  if (!texture_) {
+    // Generate the texture object
+    texture_ = CreateTextureObject(target);
+    // Generate the framebuffer object
+    glGenFramebuffersEXT(1, &fbo_);
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_);
+    bound_fbo_ = fbo_;
+    if (attributes_.depth || attributes_.stencil)
+      glGenRenderbuffersEXT(1, &depth_stencil_buffer_);
+    // Generate the multisample framebuffer object
+    if (attributes_.antialias) {
+      glGenFramebuffersEXT(1, &multisample_fbo_);
+      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, multisample_fbo_);
+      bound_fbo_ = multisample_fbo_;
+      glGenRenderbuffersEXT(1, &multisample_color_buffer_);
+      if (attributes_.depth || attributes_.stencil)
+        glGenRenderbuffersEXT(1, &multisample_depth_stencil_buffer_);
+    }
+  }
+
+  GLint internal_multisampled_color_format = 0;
+  GLint internal_color_format = 0;
+  GLint color_format = 0;
+  GLint internal_depth_stencil_format = 0;
+  if (attributes_.alpha) {
+    // GL_RGBA8_OES == GL_RGBA8
+    internal_multisampled_color_format = GL_RGBA8;
+    internal_color_format = is_gles2_ ? GL_RGBA : GL_RGBA8;
+    color_format = GL_RGBA;
+  } else {
+    // GL_RGB8_OES == GL_RGB8
+    internal_multisampled_color_format = GL_RGB8;
+    internal_color_format = is_gles2_ ? GL_RGB : GL_RGB8;
+    color_format = GL_RGB;
+  }
+  if (attributes_.stencil || attributes_.depth) {
+    // We don't allow the logic where stencil is required and depth is not.
+    // See GraphicsContext3DInternal constructor.
+    if (attributes_.stencil && attributes_.depth) {
+      internal_depth_stencil_format = GL_DEPTH24_STENCIL8_EXT;
+    } else {
+      if (is_gles2_)
+        internal_depth_stencil_format = GL_DEPTH_COMPONENT16;
+      else
+        internal_depth_stencil_format = GL_DEPTH_COMPONENT;
+    }
+  }
+
+  bool must_restore_fbo = false;
+
+  // Resize multisampling FBO
+  if (attributes_.antialias) {
+    GLint max_sample_count;
+    glGetIntegerv(GL_MAX_SAMPLES_EXT, &max_sample_count);
+    GLint sample_count = std::min(8, max_sample_count);
+    if (bound_fbo_ != multisample_fbo_) {
+      must_restore_fbo = true;
+      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, multisample_fbo_);
+    }
+    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, multisample_color_buffer_);
+    if (have_ext_framebuffer_multisample_) {
+      glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT,
+                                          sample_count,
+                                          internal_multisampled_color_format,
+                                          width,
+                                          height);
+    } else {
+      DCHECK(have_angle_framebuffer_multisample_);
+      glRenderbufferStorageMultisampleANGLE(GL_RENDERBUFFER_EXT,
+                                            sample_count,
+                                            internal_multisampled_color_format,
+                                            width,
+                                            height);
+    }
+    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+                                 GL_COLOR_ATTACHMENT0_EXT,
+                                 GL_RENDERBUFFER_EXT,
+                                 multisample_color_buffer_);
+    if (attributes_.stencil || attributes_.depth) {
+      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT,
+                            multisample_depth_stencil_buffer_);
+      if (have_ext_framebuffer_multisample_) {
+        glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT,
+                                            sample_count,
+                                            internal_depth_stencil_format,
+                                            width,
+                                            height);
+      } else {
+        DCHECK(have_angle_framebuffer_multisample_);
+        glRenderbufferStorageMultisampleANGLE(GL_RENDERBUFFER_EXT,
+                                              sample_count,
+                                              internal_depth_stencil_format,
+                                              width,
+                                              height);
+      }
+      if (attributes_.stencil)
+        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+                                     GL_STENCIL_ATTACHMENT_EXT,
+                                     GL_RENDERBUFFER_EXT,
+                                     multisample_depth_stencil_buffer_);
+      if (attributes_.depth)
+        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+                                     GL_DEPTH_ATTACHMENT_EXT,
+                                     GL_RENDERBUFFER_EXT,
+                                     multisample_depth_stencil_buffer_);
+    }
+    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);
+    GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
+      LOG(ERROR) << "Multisampling framebuffer was incomplete";
+
+      // FIXME: cleanup.
+      NOTIMPLEMENTED();
+    }
+  }
+
+  // Resize regular FBO
+  if (bound_fbo_ != fbo_) {
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_);
+    must_restore_fbo = true;
+  }
+  glBindTexture(target, texture_);
+  glTexImage2D(target, 0, internal_color_format,
+               width, height,
+               0, color_format, GL_UNSIGNED_BYTE, 0);
+  glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
+                            GL_COLOR_ATTACHMENT0_EXT,
+                            target,
+                            texture_,
+                            0);
+  glBindTexture(target, 0);
+  if (!attributes_.antialias && (attributes_.stencil || attributes_.depth)) {
+    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depth_stencil_buffer_);
+    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT,
+                             internal_depth_stencil_format,
+                             width, height);
+    if (attributes_.stencil)
+      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+                                   GL_STENCIL_ATTACHMENT_EXT,
+                                   GL_RENDERBUFFER_EXT,
+                                   depth_stencil_buffer_);
+    if (attributes_.depth)
+      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+                                   GL_DEPTH_ATTACHMENT_EXT,
+                                   GL_RENDERBUFFER_EXT,
+                                   depth_stencil_buffer_);
+    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);
+  }
+  GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+  if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
+    LOG(ERROR) << "Framebuffer was incomplete";
+
+    // FIXME: cleanup.
+    NOTIMPLEMENTED();
+  }
+
+  if (attributes_.antialias) {
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, multisample_fbo_);
+    if (bound_fbo_ == multisample_fbo_)
+      must_restore_fbo = false;
+  }
+
+  // Initialize renderbuffers to 0.
+  GLfloat clearColor[] = {0, 0, 0, 0}, clearDepth = 0;
+  GLint clearStencil = 0;
+  GLboolean colorMask[] = {GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE};
+  GLboolean depthMask = GL_TRUE;
+  GLuint stencilMask = 0xffffffff;
+  GLboolean isScissorEnabled = GL_FALSE;
+  GLboolean isDitherEnabled = GL_FALSE;
+  GLbitfield clearMask = GL_COLOR_BUFFER_BIT;
+  glGetFloatv(GL_COLOR_CLEAR_VALUE, clearColor);
+  glClearColor(0, 0, 0, 0);
+  glGetBooleanv(GL_COLOR_WRITEMASK, colorMask);
+  glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+  if (attributes_.depth) {
+    glGetFloatv(GL_DEPTH_CLEAR_VALUE, &clearDepth);
+    glClearDepth(1);
+    glGetBooleanv(GL_DEPTH_WRITEMASK, &depthMask);
+    glDepthMask(GL_TRUE);
+    clearMask |= GL_DEPTH_BUFFER_BIT;
+  }
+  if (attributes_.stencil) {
+    glGetIntegerv(GL_STENCIL_CLEAR_VALUE, &clearStencil);
+    glClearStencil(0);
+    glGetIntegerv(GL_STENCIL_WRITEMASK,
+                  reinterpret_cast<GLint*>(&stencilMask));
+    glStencilMaskSeparate(GL_FRONT, 0xffffffff);
+    clearMask |= GL_STENCIL_BUFFER_BIT;
+  }
+  isScissorEnabled = glIsEnabled(GL_SCISSOR_TEST);
+  glDisable(GL_SCISSOR_TEST);
+  isDitherEnabled = glIsEnabled(GL_DITHER);
+  glDisable(GL_DITHER);
+
+  glClear(clearMask);
+
+  glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
+  glColorMask(colorMask[0], colorMask[1], colorMask[2], colorMask[3]);
+  if (attributes_.depth) {
+    glClearDepth(clearDepth);
+    glDepthMask(depthMask);
+  }
+  if (attributes_.stencil) {
+    glClearStencil(clearStencil);
+    glStencilMaskSeparate(GL_FRONT, stencilMask);
+  }
+  if (isScissorEnabled)
+    glEnable(GL_SCISSOR_TEST);
+  else
+    glDisable(GL_SCISSOR_TEST);
+  if (isDitherEnabled)
+    glEnable(GL_DITHER);
+  else
+    glDisable(GL_DITHER);
+
+  if (must_restore_fbo)
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+
+#ifdef FLIP_FRAMEBUFFER_VERTICALLY
+  if (scanline_) {
+    delete[] scanline_;
+    scanline_ = 0;
+  }
+  scanline_ = new unsigned char[width * 4];
+#endif  // FLIP_FRAMEBUFFER_VERTICALLY
+}
+
+#ifdef FLIP_FRAMEBUFFER_VERTICALLY
+void WebGraphicsContext3DInProcessImpl::FlipVertically(
+    unsigned char* framebuffer, unsigned int width, unsigned int height) {
+  unsigned char* scanline = scanline_;
+  if (!scanline)
+    return;
+  unsigned int row_bytes = width * 4;
+  unsigned int count = height / 2;
+  for (unsigned int i = 0; i < count; i++) {
+    unsigned char* row_a = framebuffer + i * row_bytes;
+    unsigned char* row_b = framebuffer + (height - i - 1) * row_bytes;
+    // FIXME: this is where the multiplication of the alpha
+    // channel into the color buffer will need to occur if the
+    // user specifies the "premultiplyAlpha" flag in the context
+    // creation attributes.
+    memcpy(scanline, row_b, row_bytes);
+    memcpy(row_b, row_a, row_bytes);
+    memcpy(row_a, scanline, row_bytes);
+  }
+}
+#endif
+
+bool WebGraphicsContext3DInProcessImpl::readBackFramebuffer(
+    unsigned char* pixels, size_t bufferSize) {
+  if (bufferSize != static_cast<size_t>(4 * width() * height()))
+    return false;
+
+  makeContextCurrent();
+
+  // Earlier versions of this code used the GPU to flip the
+  // framebuffer vertically before reading it back for compositing
+  // via software. This code was quite complicated, used a lot of
+  // GPU memory, and didn't provide an obvious speedup. Since this
+  // vertical flip is only a temporary solution anyway until Chrome
+  // is fully GPU composited, it wasn't worth the complexity.
+
+  ResolveMultisampledFramebuffer(0, 0, cached_width_, cached_height_);
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_);
+
+  GLint pack_alignment = 4;
+  bool must_restore_pack_alignment = false;
+  glGetIntegerv(GL_PACK_ALIGNMENT, &pack_alignment);
+  if (pack_alignment > 4) {
+    glPixelStorei(GL_PACK_ALIGNMENT, 4);
+    must_restore_pack_alignment = true;
+  }
+
+  if (is_gles2_) {
+    // FIXME: consider testing for presence of GL_OES_read_format
+    // and GL_EXT_read_format_bgra, and using GL_BGRA_EXT here
+    // directly.
+    glReadPixels(0, 0, cached_width_, cached_height_,
+                 GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+    for (size_t i = 0; i < bufferSize; i += 4) {
+      std::swap(pixels[i], pixels[i + 2]);
+    }
+  } else {
+    glReadPixels(0, 0, cached_width_, cached_height_,
+                 GL_BGRA, GL_UNSIGNED_BYTE, pixels);
+  }
+
+  if (must_restore_pack_alignment)
+    glPixelStorei(GL_PACK_ALIGNMENT, pack_alignment);
+
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+
+#ifdef FLIP_FRAMEBUFFER_VERTICALLY
+  if (pixels)
+    FlipVertically(pixels, cached_width_, cached_height_);
+#endif
+
+  return true;
+}
+
+void WebGraphicsContext3DInProcessImpl::synthesizeGLError(unsigned long error) {
+  if (synthetic_errors_set_.find(error) == synthetic_errors_set_.end()) {
+    synthetic_errors_set_.insert(error);
+    synthetic_errors_list_.push_back(error);
+  }
+}
+
+void* WebGraphicsContext3DInProcessImpl::mapBufferSubDataCHROMIUM(
+    unsigned target, int offset, int size, unsigned access) {
+  return 0;
+}
+
+void WebGraphicsContext3DInProcessImpl::unmapBufferSubDataCHROMIUM(
+    const void* mem) {
+}
+
+void* WebGraphicsContext3DInProcessImpl::mapTexSubImage2DCHROMIUM(
+    unsigned target, int level, int xoffset, int yoffset,
+    int width, int height, unsigned format, unsigned type, unsigned access) {
+  return 0;
+}
+
+void WebGraphicsContext3DInProcessImpl::unmapTexSubImage2DCHROMIUM(
+    const void* mem) {
+}
+
+void WebGraphicsContext3DInProcessImpl::copyTextureToParentTextureCHROMIUM(
+    unsigned id, unsigned id2) {
+  if (!glGetTexLevelParameteriv)
+    return;
+
+  makeContextCurrent();
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, copy_texture_to_parent_texture_fbo_);
+  glFramebufferTexture2DEXT(GL_FRAMEBUFFER,
+                            GL_COLOR_ATTACHMENT0,
+                            GL_TEXTURE_2D,
+                            id,
+                            0);  // level
+  glBindTexture(GL_TEXTURE_2D, id2);
+  GLsizei width, height;
+  glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &width);
+  glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &height);
+  glCopyTexImage2D(GL_TEXTURE_2D,
+                   0,  // level
+                   GL_RGBA,
+                   0, 0,  // x, y
+                   width,
+                   height,
+                   0);  // border
+  glBindTexture(GL_TEXTURE_2D, bound_texture_);
+  glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+}
+
+WebString WebGraphicsContext3DInProcessImpl::
+    getRequestableExtensionsCHROMIUM() {
+  return WebString();
+}
+
+void WebGraphicsContext3DInProcessImpl::requestExtensionCHROMIUM(const char*) {
+}
+
+// Helper macros to reduce the amount of code.
+
+#define DELEGATE_TO_GL(name, glname)                                           \
+void WebGraphicsContext3DInProcessImpl::name() {                               \
+  makeContextCurrent();                                                        \
+  gl##glname();                                                                \
+}
+
+#define DELEGATE_TO_GL_1(name, glname, t1)                                     \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1) {                          \
+  makeContextCurrent();                                                        \
+  gl##glname(a1);                                                              \
+}
+
+#define DELEGATE_TO_GL_1_C(name, glname, t1)                                   \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1) {                          \
+  makeContextCurrent();                                                        \
+  gl##glname(static_cast<GLclampf>(a1));                                       \
+}
+
+#define DELEGATE_TO_GL_1R(name, glname, t1, rt)                                \
+rt WebGraphicsContext3DInProcessImpl::name(t1 a1) {                            \
+  makeContextCurrent();                                                        \
+  return gl##glname(a1);                                                       \
+}
+
+#define DELEGATE_TO_GL_1RB(name, glname, t1, rt)                               \
+rt WebGraphicsContext3DInProcessImpl::name(t1 a1) {                            \
+  makeContextCurrent();                                                        \
+  return gl##glname(a1) ? true : false;                                        \
+}
+
+#define DELEGATE_TO_GL_2(name, glname, t1, t2)                                 \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2) {                   \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2);                                                          \
+}
+
+#define DELEGATE_TO_GL_2_C1(name, glname, t1, t2)                              \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2) {                   \
+  makeContextCurrent();                                                        \
+  gl##glname(static_cast<GLclampf>(a1), a2);                                   \
+}
+
+#define DELEGATE_TO_GL_2_C12(name, glname, t1, t2)                             \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2) {                   \
+  makeContextCurrent();                                                        \
+  gl##glname(static_cast<GLclampf>(a1), static_cast<GLclampf>(a2));            \
+}
+
+#define DELEGATE_TO_GL_2R(name, glname, t1, t2, rt)                            \
+rt WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2) {                     \
+  makeContextCurrent();                                                        \
+  return gl##glname(a1, a2);                                                   \
+}
+
+#define DELEGATE_TO_GL_3(name, glname, t1, t2, t3)                             \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3) {            \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3);                                                      \
+}
+
+#define DELEGATE_TO_GL_4(name, glname, t1, t2, t3, t4)                         \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4) {     \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3, a4);                                                  \
+}
+
+#define DELEGATE_TO_GL_4_C1234(name, glname, t1, t2, t3, t4)                   \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4) {     \
+  makeContextCurrent();                                                        \
+  gl##glname(static_cast<GLclampf>(a1), static_cast<GLclampf>(a2),             \
+             static_cast<GLclampf>(a3), static_cast<GLclampf>(a4));            \
+}
+
+#define DELEGATE_TO_GL_5(name, glname, t1, t2, t3, t4, t5)                     \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4,       \
+                                             t5 a5) {                          \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3, a4, a5);                                              \
+}
+
+#define DELEGATE_TO_GL_6(name, glname, t1, t2, t3, t4, t5, t6)                 \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4,       \
+                                             t5 a5, t6 a6) {                   \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3, a4, a5, a6);                                          \
+}
+
+#define DELEGATE_TO_GL_7(name, glname, t1, t2, t3, t4, t5, t6, t7)             \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4,       \
+                                             t5 a5, t6 a6, t7 a7) {            \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3, a4, a5, a6, a7);                                      \
+}
+
+#define DELEGATE_TO_GL_8(name, glname, t1, t2, t3, t4, t5, t6, t7, t8)         \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4,       \
+                                             t5 a5, t6 a6, t7 a7, t8 a8) {     \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3, a4, a5, a6, a7, a8);                                  \
+}
+
+#define DELEGATE_TO_GL_9(name, glname, t1, t2, t3, t4, t5, t6, t7, t8, t9)     \
+void WebGraphicsContext3DInProcessImpl::name(t1 a1, t2 a2, t3 a3, t4 a4,       \
+                                             t5 a5, t6 a6, t7 a7, t8 a8,       \
+                                             t9 a9) {                          \
+  makeContextCurrent();                                                        \
+  gl##glname(a1, a2, a3, a4, a5, a6, a7, a8, a9);                              \
+}
+
+void WebGraphicsContext3DInProcessImpl::activeTexture(unsigned long texture) {
+  // FIXME: query number of textures available.
+  if (texture < GL_TEXTURE0 || texture > GL_TEXTURE0+32)
+    // FIXME: raise exception.
+    return;
+
+  makeContextCurrent();
+  glActiveTexture(texture);
+}
+
+DELEGATE_TO_GL_2(attachShader, AttachShader, WebGLId, WebGLId)
+
+DELEGATE_TO_GL_3(bindAttribLocation, BindAttribLocation,
+                 WebGLId, unsigned long, const char*)
+
+void WebGraphicsContext3DInProcessImpl::bindBuffer(
+    unsigned long target, WebGLId buffer) {
+  makeContextCurrent();
+  if (target == GL_ARRAY_BUFFER)
+    bound_array_buffer_ = buffer;
+  glBindBuffer(target, buffer);
+}
+
+void WebGraphicsContext3DInProcessImpl::bindFramebuffer(
+    unsigned long target, WebGLId framebuffer) {
+  makeContextCurrent();
+  if (!framebuffer)
+    framebuffer = (attributes_.antialias ? multisample_fbo_ : fbo_);
+  if (framebuffer != bound_fbo_) {
+    glBindFramebufferEXT(target, framebuffer);
+    bound_fbo_ = framebuffer;
+  }
+}
+
+DELEGATE_TO_GL_2(bindRenderbuffer, BindRenderbufferEXT, unsigned long, WebGLId)
+
+void WebGraphicsContext3DInProcessImpl::bindTexture(
+    unsigned long target, WebGLId texture) {
+  makeContextCurrent();
+  glBindTexture(target, texture);
+  bound_texture_ = texture;
+}
+
+DELEGATE_TO_GL_4_C1234(blendColor, BlendColor, double, double, double, double)
+
+DELEGATE_TO_GL_1(blendEquation, BlendEquation, unsigned long)
+
+DELEGATE_TO_GL_2(blendEquationSeparate, BlendEquationSeparate,
+                 unsigned long, unsigned long)
+
+DELEGATE_TO_GL_2(blendFunc, BlendFunc, unsigned long, unsigned long)
+
+DELEGATE_TO_GL_4(blendFuncSeparate, BlendFuncSeparate,
+                 unsigned long, unsigned long, unsigned long, unsigned long)
+
+DELEGATE_TO_GL_4(bufferData, BufferData,
+                 unsigned long, int, const void*, unsigned long)
+
+DELEGATE_TO_GL_4(bufferSubData, BufferSubData,
+                 unsigned long, long, int, const void*)
+
+DELEGATE_TO_GL_1R(checkFramebufferStatus, CheckFramebufferStatusEXT,
+                  unsigned long, unsigned long)
+
+DELEGATE_TO_GL_1(clear, Clear, unsigned long)
+
+DELEGATE_TO_GL_4_C1234(clearColor, ClearColor, double, double, double, double)
+
+DELEGATE_TO_GL_1(clearDepth, ClearDepth, double)
+
+DELEGATE_TO_GL_1(clearStencil, ClearStencil, long)
+
+DELEGATE_TO_GL_4(colorMask, ColorMask, bool, bool, bool, bool)
+
+void WebGraphicsContext3DInProcessImpl::compileShader(WebGLId shader) {
+  makeContextCurrent();
+
+  ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+  if (result == shader_source_map_.end()) {
+    // Passing down to gl driver to generate the correct error; or the case
+    // where the shader deletion is delayed when it's attached to a program.
+    glCompileShader(shader);
+    return;
+  }
+  ShaderSourceEntry* entry = result->second;
+  DCHECK(entry);
+
+  if (!AngleValidateShaderSource(entry)) {
+    // Shader didn't validate; don't move forward with compiling
+    // translated source.
+    return;
+  }
+
+  const char* translated_source = entry->translated_source.get();
+  int shader_length = translated_source ? strlen(translated_source) : 0;
+  glShaderSource(
+      shader, 1, const_cast<const char**>(&translated_source), &shader_length);
+  glCompileShader(shader);
+
+#ifndef NDEBUG
+  int compileStatus;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &compileStatus);
+  // DCHECK that ANGLE generated GLSL will be accepted by OpenGL
+  DCHECK(compileStatus == GL_TRUE);
+#endif
+}
+
+void WebGraphicsContext3DInProcessImpl::copyTexImage2D(
+    unsigned long target, long level, unsigned long internalformat,
+    long x, long y, unsigned long width, unsigned long height, long border) {
+  makeContextCurrent();
+
+  bool needsResolve = (attributes_.antialias && bound_fbo_ == multisample_fbo_);
+  if (needsResolve) {
+    ResolveMultisampledFramebuffer(x, y, width, height);
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_);
+  }
+
+  glCopyTexImage2D(target, level, internalformat, x, y, width, height, border);
+
+  if (needsResolve)
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+}
+
+void WebGraphicsContext3DInProcessImpl::copyTexSubImage2D(
+    unsigned long target, long level, long xoffset, long yoffset,
+    long x, long y, unsigned long width, unsigned long height) {
+  makeContextCurrent();
+
+  bool needsResolve = (attributes_.antialias && bound_fbo_ == multisample_fbo_);
+  if (needsResolve) {
+    ResolveMultisampledFramebuffer(x, y, width, height);
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_);
+  }
+
+  glCopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
+
+  if (needsResolve)
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+}
+
+DELEGATE_TO_GL_1(cullFace, CullFace, unsigned long)
+
+DELEGATE_TO_GL_1(depthFunc, DepthFunc, unsigned long)
+
+DELEGATE_TO_GL_1(depthMask, DepthMask, bool)
+
+DELEGATE_TO_GL_2(depthRange, DepthRange, double, double)
+
+DELEGATE_TO_GL_2(detachShader, DetachShader, WebGLId, WebGLId)
+
+DELEGATE_TO_GL_1(disable, Disable, unsigned long)
+
+void WebGraphicsContext3DInProcessImpl::disableVertexAttribArray(
+    unsigned long index) {
+  makeContextCurrent();
+  if (index < kNumTrackedPointerStates)
+    vertex_attrib_pointer_state_[index].enabled = false;
+  glDisableVertexAttribArray(index);
+}
+
+DELEGATE_TO_GL_3(drawArrays, DrawArrays, unsigned long, long, long)
+
+void WebGraphicsContext3DInProcessImpl::drawElements(
+    unsigned long mode, unsigned long count, unsigned long type, long offset) {
+  makeContextCurrent();
+  glDrawElements(mode, count, type,
+                 reinterpret_cast<void*>(static_cast<intptr_t>(offset)));
+}
+
+DELEGATE_TO_GL_1(enable, Enable, unsigned long)
+
+void WebGraphicsContext3DInProcessImpl::enableVertexAttribArray(
+    unsigned long index) {
+  makeContextCurrent();
+  if (index < kNumTrackedPointerStates)
+    vertex_attrib_pointer_state_[index].enabled = true;
+  glEnableVertexAttribArray(index);
+}
+
+DELEGATE_TO_GL(finish, Finish)
+
+DELEGATE_TO_GL(flush, Flush)
+
+DELEGATE_TO_GL_4(framebufferRenderbuffer, FramebufferRenderbufferEXT,
+                 unsigned long, unsigned long, unsigned long, WebGLId)
+
+DELEGATE_TO_GL_5(framebufferTexture2D, FramebufferTexture2DEXT,
+                 unsigned long, unsigned long, unsigned long, WebGLId, long)
+
+DELEGATE_TO_GL_1(frontFace, FrontFace, unsigned long)
+
+void WebGraphicsContext3DInProcessImpl::generateMipmap(unsigned long target) {
+  makeContextCurrent();
+  if (is_gles2_ || have_ext_framebuffer_object_)
+    glGenerateMipmapEXT(target);
+  // FIXME: provide alternative code path? This will be unpleasant
+  // to implement if glGenerateMipmapEXT is not available -- it will
+  // require a texture readback and re-upload.
+}
+
+bool WebGraphicsContext3DInProcessImpl::getActiveAttrib(
+    WebGLId program, unsigned long index, ActiveInfo& info) {
+  makeContextCurrent();
+  if (!program) {
+    synthesizeGLError(GL_INVALID_VALUE);
+    return false;
+  }
+  GLint max_name_length = -1;
+  glGetProgramiv(program, GL_ACTIVE_ATTRIBUTE_MAX_LENGTH, &max_name_length);
+  if (max_name_length < 0)
+    return false;
+  scoped_array<GLchar> name(new GLchar[max_name_length]);
+  GLsizei length = 0;
+  GLint size = -1;
+  GLenum type = 0;
+  glGetActiveAttrib(program, index, max_name_length,
+                    &length, &size, &type, name.get());
+  if (size < 0) {
+    return false;
+  }
+  info.name = WebString::fromUTF8(name.get(), length);
+  info.type = type;
+  info.size = size;
+  return true;
+}
+
+bool WebGraphicsContext3DInProcessImpl::getActiveUniform(
+    WebGLId program, unsigned long index, ActiveInfo& info) {
+  makeContextCurrent();
+  GLint max_name_length = -1;
+  glGetProgramiv(program, GL_ACTIVE_UNIFORM_MAX_LENGTH, &max_name_length);
+  if (max_name_length < 0)
+    return false;
+  scoped_array<GLchar> name(new GLchar[max_name_length]);
+  GLsizei length = 0;
+  GLint size = -1;
+  GLenum type = 0;
+  glGetActiveUniform(program, index, max_name_length,
+                     &length, &size, &type, name.get());
+  if (size < 0) {
+    return false;
+  }
+  info.name = WebString::fromUTF8(name.get(), length);
+  info.type = type;
+  info.size = size;
+  return true;
+}
+
+DELEGATE_TO_GL_4(getAttachedShaders, GetAttachedShaders,
+                 WebGLId, int, int*, unsigned int*)
+
+DELEGATE_TO_GL_2R(getAttribLocation, GetAttribLocation,
+                  WebGLId, const char*, int)
+
+DELEGATE_TO_GL_2(getBooleanv, GetBooleanv,
+                 unsigned long, unsigned char*)
+
+DELEGATE_TO_GL_3(getBufferParameteriv, GetBufferParameteriv,
+                 unsigned long, unsigned long, int*)
+
+WebGraphicsContext3D::Attributes WebGraphicsContext3DInProcessImpl::
+    getContextAttributes() {
+  return attributes_;
+}
+
+unsigned long WebGraphicsContext3DInProcessImpl::getError() {
+  DCHECK(synthetic_errors_list_.size() == synthetic_errors_set_.size());
+  if (synthetic_errors_set_.size() > 0) {
+    unsigned long error = synthetic_errors_list_.front();
+    synthetic_errors_list_.pop_front();
+    synthetic_errors_set_.erase(error);
+    return error;
+  }
+
+  makeContextCurrent();
+  return glGetError();
+}
+
+bool WebGraphicsContext3DInProcessImpl::isContextLost() {
+  return false;
+}
+
+DELEGATE_TO_GL_2(getFloatv, GetFloatv, unsigned long, float*)
+
+void WebGraphicsContext3DInProcessImpl::getFramebufferAttachmentParameteriv(
+    unsigned long target, unsigned long attachment,
+    unsigned long pname, int* value) {
+  makeContextCurrent();
+  if (attachment == GL_DEPTH_STENCIL_ATTACHMENT)
+    attachment = GL_DEPTH_ATTACHMENT;  // Or GL_STENCIL_ATTACHMENT;
+                                       // either works.
+  glGetFramebufferAttachmentParameterivEXT(target, attachment, pname, value);
+}
+
+void WebGraphicsContext3DInProcessImpl::getIntegerv(
+    unsigned long pname, int* value) {
+  makeContextCurrent();
+  if (is_gles2_) {
+    glGetIntegerv(pname, value);
+    return;
+  }
+  // Need to emulate MAX_FRAGMENT/VERTEX_UNIFORM_VECTORS and
+  // MAX_VARYING_VECTORS because desktop GL's corresponding queries
+  // return the number of components whereas GLES2 return the number
+  // of vectors (each vector has 4 components).  Therefore, the value
+  // returned by desktop GL needs to be divided by 4.
+  switch (pname) {
+  case MAX_FRAGMENT_UNIFORM_VECTORS:
+    glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_COMPONENTS, value);
+    *value /= 4;
+    break;
+  case MAX_VERTEX_UNIFORM_VECTORS:
+    glGetIntegerv(GL_MAX_VERTEX_UNIFORM_COMPONENTS, value);
+    *value /= 4;
+    break;
+  case MAX_VARYING_VECTORS:
+    glGetIntegerv(GL_MAX_VARYING_FLOATS, value);
+    *value /= 4;
+    break;
+  default:
+    glGetIntegerv(pname, value);
+  }
+}
+
+DELEGATE_TO_GL_3(getProgramiv, GetProgramiv, WebGLId, unsigned long, int*)
+
+WebString WebGraphicsContext3DInProcessImpl::getProgramInfoLog(
+    WebGLId program) {
+  makeContextCurrent();
+  GLint log_length;
+  glGetProgramiv(program, GL_INFO_LOG_LENGTH, &log_length);
+  if (!log_length)
+    return WebString();
+  scoped_array<GLchar> log(new GLchar[log_length]);
+  GLsizei returned_log_length;
+  glGetProgramInfoLog(program, log_length, &returned_log_length, log.get());
+  DCHECK(log_length == returned_log_length + 1);
+  WebString res = WebString::fromUTF8(log.get(), returned_log_length);
+  return res;
+}
+
+DELEGATE_TO_GL_3(getRenderbufferParameteriv, GetRenderbufferParameterivEXT,
+                 unsigned long, unsigned long, int*)
+
+void WebGraphicsContext3DInProcessImpl::getShaderiv(
+    WebGLId shader, unsigned long pname, int* value) {
+  makeContextCurrent();
+
+  ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+  if (result != shader_source_map_.end()) {
+    ShaderSourceEntry* entry = result->second;
+    DCHECK(entry);
+    switch (pname) {
+      case GL_COMPILE_STATUS:
+        if (!entry->is_valid) {
+          *value = 0;
+          return;
+        }
+        break;
+      case GL_INFO_LOG_LENGTH:
+        if (!entry->is_valid) {
+          *value = entry->log.get() ? strlen(entry->log.get()) : 0;
+          if (*value)
+            (*value)++;
+          return;
+        }
+        break;
+      case GL_SHADER_SOURCE_LENGTH:
+        *value = entry->source.get() ? strlen(entry->source.get()) : 0;
+        if (*value)
+          (*value)++;
+        return;
+    }
+  }
+
+  glGetShaderiv(shader, pname, value);
+}
+
+WebString WebGraphicsContext3DInProcessImpl::getShaderInfoLog(WebGLId shader) {
+  makeContextCurrent();
+
+  ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+  if (result != shader_source_map_.end()) {
+    ShaderSourceEntry* entry = result->second;
+    DCHECK(entry);
+    if (!entry->is_valid) {
+      if (!entry->log.get())
+        return WebString();
+      WebString res = WebString::fromUTF8(
+          entry->log.get(), strlen(entry->log.get()));
+      return res;
+    }
+  }
+
+  GLint log_length = 0;
+  glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_length);
+  if (log_length <= 1)
+    return WebString();
+  scoped_array<GLchar> log(new GLchar[log_length]);
+  GLsizei returned_log_length;
+  glGetShaderInfoLog(shader, log_length, &returned_log_length, log.get());
+  DCHECK(log_length == returned_log_length + 1);
+  WebString res = WebString::fromUTF8(log.get(), returned_log_length);
+  return res;
+}
+
+WebString WebGraphicsContext3DInProcessImpl::getShaderSource(WebGLId shader) {
+  makeContextCurrent();
+
+  ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+  if (result != shader_source_map_.end()) {
+    ShaderSourceEntry* entry = result->second;
+    DCHECK(entry);
+    if (!entry->source.get())
+      return WebString();
+    WebString res = WebString::fromUTF8(
+        entry->source.get(), strlen(entry->source.get()));
+    return res;
+  }
+
+  GLint log_length = 0;
+  glGetShaderiv(shader, GL_SHADER_SOURCE_LENGTH, &log_length);
+  if (log_length <= 1)
+    return WebString();
+  scoped_array<GLchar> log(new GLchar[log_length]);
+  GLsizei returned_log_length;
+  glGetShaderSource(shader, log_length, &returned_log_length, log.get());
+  DCHECK(log_length == returned_log_length + 1);
+  WebString res = WebString::fromUTF8(log.get(), returned_log_length);
+  return res;
+}
+
+WebString WebGraphicsContext3DInProcessImpl::getString(unsigned long name) {
+  makeContextCurrent();
+  std::string result(reinterpret_cast<const char*>(glGetString(name)));
+  if (name == GL_EXTENSIONS) {
+    // GL_CHROMIUM_copy_texture_to_parent_texture requires the
+    // desktopGL-only function glGetTexLevelParameteriv (GLES2
+    // doesn't support it).
+    if (!is_gles2_)
+      result += " GL_CHROMIUM_copy_texture_to_parent_texture";
+  }
+  return WebString::fromUTF8(result.c_str());
+}
+
+DELEGATE_TO_GL_3(getTexParameterfv, GetTexParameterfv,
+                 unsigned long, unsigned long, float*)
+
+DELEGATE_TO_GL_3(getTexParameteriv, GetTexParameteriv,
+                 unsigned long, unsigned long, int*)
+
+DELEGATE_TO_GL_3(getUniformfv, GetUniformfv, WebGLId, long, float*)
+
+DELEGATE_TO_GL_3(getUniformiv, GetUniformiv, WebGLId, long, int*)
+
+DELEGATE_TO_GL_2R(getUniformLocation, GetUniformLocation,
+                  WebGLId, const char*, long)
+
+DELEGATE_TO_GL_3(getVertexAttribfv, GetVertexAttribfv,
+                 unsigned long, unsigned long, float*)
+
+DELEGATE_TO_GL_3(getVertexAttribiv, GetVertexAttribiv,
+                 unsigned long, unsigned long, int*)
+
+long WebGraphicsContext3DInProcessImpl::getVertexAttribOffset(
+    unsigned long index, unsigned long pname) {
+  makeContextCurrent();
+  void* pointer;
+  glGetVertexAttribPointerv(index, pname, &pointer);
+  return reinterpret_cast<long>(pointer);
+}
+
+DELEGATE_TO_GL_2(hint, Hint, unsigned long, unsigned long)
+
+DELEGATE_TO_GL_1RB(isBuffer, IsBuffer, WebGLId, bool)
+
+DELEGATE_TO_GL_1RB(isEnabled, IsEnabled, unsigned long, bool)
+
+DELEGATE_TO_GL_1RB(isFramebuffer, IsFramebufferEXT, WebGLId, bool)
+
+DELEGATE_TO_GL_1RB(isProgram, IsProgram, WebGLId, bool)
+
+DELEGATE_TO_GL_1RB(isRenderbuffer, IsRenderbufferEXT, WebGLId, bool)
+
+DELEGATE_TO_GL_1RB(isShader, IsShader, WebGLId, bool)
+
+DELEGATE_TO_GL_1RB(isTexture, IsTexture, WebGLId, bool)
+
+DELEGATE_TO_GL_1_C(lineWidth, LineWidth, double)
+
+DELEGATE_TO_GL_1(linkProgram, LinkProgram, WebGLId)
+
+DELEGATE_TO_GL_2(pixelStorei, PixelStorei, unsigned long, long)
+
+DELEGATE_TO_GL_2_C12(polygonOffset, PolygonOffset, double, double)
+
+void WebGraphicsContext3DInProcessImpl::readPixels(
+    long x, long y, unsigned long width, unsigned long height,
+    unsigned long format, unsigned long type, void* pixels) {
+  makeContextCurrent();
+  // FIXME: remove the two glFlush calls when the driver bug is fixed, i.e.,
+  // all previous rendering calls should be done before reading pixels.
+  glFlush();
+  bool needs_resolve =
+      (attributes_.antialias && bound_fbo_ == multisample_fbo_);
+  if (needs_resolve) {
+    ResolveMultisampledFramebuffer(x, y, width, height);
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo_);
+    glFlush();
+  }
+
+  glReadPixels(x, y, width, height, format, type, pixels);
+
+  if (needs_resolve)
+    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, bound_fbo_);
+}
+
+void WebGraphicsContext3DInProcessImpl::releaseShaderCompiler() {
+}
+
+void WebGraphicsContext3DInProcessImpl::renderbufferStorage(
+    unsigned long target,
+    unsigned long internalformat,
+    unsigned long width,
+    unsigned long height) {
+  makeContextCurrent();
+  switch (internalformat) {
+  case GL_DEPTH_STENCIL:
+    internalformat = GL_DEPTH24_STENCIL8_EXT;
+    break;
+  case GL_DEPTH_COMPONENT16:
+    internalformat = GL_DEPTH_COMPONENT;
+    break;
+  case GL_RGBA4:
+  case GL_RGB5_A1:
+    internalformat = GL_RGBA;
+    break;
+  case 0x8D62:  // GL_RGB565
+    internalformat = GL_RGB;
+    break;
+  }
+  glRenderbufferStorageEXT(target, internalformat, width, height);
+}
+
+DELEGATE_TO_GL_2_C1(sampleCoverage, SampleCoverage, double, bool)
+
+DELEGATE_TO_GL_4(scissor, Scissor, long, long, unsigned long, unsigned long)
+
+void WebGraphicsContext3DInProcessImpl::texImage2D(
+    unsigned target, unsigned level, unsigned internalFormat,
+    unsigned width, unsigned height, unsigned border,
+    unsigned format, unsigned type, const void* pixels) {
+  if (width && height && !pixels) {
+    synthesizeGLError(GL_INVALID_VALUE);
+    return;
+  }
+  makeContextCurrent();
+  glTexImage2D(target, level, internalFormat,
+               width, height, border, format, type, pixels);
+}
+
+void WebGraphicsContext3DInProcessImpl::shaderSource(
+    WebGLId shader, const char* source) {
+  makeContextCurrent();
+  GLint length = source ? strlen(source) : 0;
+  ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+  if (result != shader_source_map_.end()) {
+    ShaderSourceEntry* entry = result->second;
+    DCHECK(entry);
+    entry->source.reset(new char[length + 1]);
+    memcpy(entry->source.get(), source, (length + 1) * sizeof(char));
+  } else {
+    glShaderSource(shader, 1, &source, &length);
+  }
+}
+
+DELEGATE_TO_GL_3(stencilFunc, StencilFunc, unsigned long, long, unsigned long)
+
+DELEGATE_TO_GL_4(stencilFuncSeparate, StencilFuncSeparate,
+                 unsigned long, unsigned long, long, unsigned long)
+
+DELEGATE_TO_GL_1(stencilMask, StencilMask, unsigned long)
+
+DELEGATE_TO_GL_2(stencilMaskSeparate, StencilMaskSeparate,
+                 unsigned long, unsigned long)
+
+DELEGATE_TO_GL_3(stencilOp, StencilOp,
+                 unsigned long, unsigned long, unsigned long)
+
+DELEGATE_TO_GL_4(stencilOpSeparate, StencilOpSeparate,
+                 unsigned long, unsigned long, unsigned long, unsigned long)
+
+DELEGATE_TO_GL_3(texParameterf, TexParameterf, unsigned, unsigned, float);
+
+DELEGATE_TO_GL_3(texParameteri, TexParameteri, unsigned, unsigned, int);
+
+DELEGATE_TO_GL_9(texSubImage2D, TexSubImage2D,
+                 unsigned, unsigned, unsigned, unsigned, unsigned,
+                 unsigned, unsigned, unsigned, const void*)
+
+DELEGATE_TO_GL_2(uniform1f, Uniform1f, long, float)
+
+DELEGATE_TO_GL_3(uniform1fv, Uniform1fv, long, int, float*)
+
+DELEGATE_TO_GL_2(uniform1i, Uniform1i, long, int)
+
+DELEGATE_TO_GL_3(uniform1iv, Uniform1iv, long, int, int*)
+
+DELEGATE_TO_GL_3(uniform2f, Uniform2f, long, float, float)
+
+DELEGATE_TO_GL_3(uniform2fv, Uniform2fv, long, int, float*)
+
+DELEGATE_TO_GL_3(uniform2i, Uniform2i, long, int, int)
+
+DELEGATE_TO_GL_3(uniform2iv, Uniform2iv, long, int, int*)
+
+DELEGATE_TO_GL_4(uniform3f, Uniform3f, long, float, float, float)
+
+DELEGATE_TO_GL_3(uniform3fv, Uniform3fv, long, int, float*)
+
+DELEGATE_TO_GL_4(uniform3i, Uniform3i, long, int, int, int)
+
+DELEGATE_TO_GL_3(uniform3iv, Uniform3iv, long, int, int*)
+
+DELEGATE_TO_GL_5(uniform4f, Uniform4f, long, float, float, float, float)
+
+DELEGATE_TO_GL_3(uniform4fv, Uniform4fv, long, int, float*)
+
+DELEGATE_TO_GL_5(uniform4i, Uniform4i, long, int, int, int, int)
+
+DELEGATE_TO_GL_3(uniform4iv, Uniform4iv, long, int, int*)
+
+DELEGATE_TO_GL_4(uniformMatrix2fv, UniformMatrix2fv,
+                 long, int, bool, const float*)
+
+DELEGATE_TO_GL_4(uniformMatrix3fv, UniformMatrix3fv,
+                 long, int, bool, const float*)
+
+DELEGATE_TO_GL_4(uniformMatrix4fv, UniformMatrix4fv,
+                 long, int, bool, const float*)
+
+DELEGATE_TO_GL_1(useProgram, UseProgram, WebGLId)
+
+DELEGATE_TO_GL_1(validateProgram, ValidateProgram, WebGLId)
+
+DELEGATE_TO_GL_2(vertexAttrib1f, VertexAttrib1f, unsigned long, float)
+
+DELEGATE_TO_GL_2(vertexAttrib1fv, VertexAttrib1fv, unsigned long, const float*)
+
+DELEGATE_TO_GL_3(vertexAttrib2f, VertexAttrib2f, unsigned long, float, float)
+
+DELEGATE_TO_GL_2(vertexAttrib2fv, VertexAttrib2fv, unsigned long, const float*)
+
+DELEGATE_TO_GL_4(vertexAttrib3f, VertexAttrib3f,
+                 unsigned long, float, float, float)
+
+DELEGATE_TO_GL_2(vertexAttrib3fv, VertexAttrib3fv, unsigned long, const float*)
+
+DELEGATE_TO_GL_5(vertexAttrib4f, VertexAttrib4f,
+                 unsigned long, float, float, float, float)
+
+DELEGATE_TO_GL_2(vertexAttrib4fv, VertexAttrib4fv, unsigned long, const float*)
+
+void WebGraphicsContext3DInProcessImpl::vertexAttribPointer(
+    unsigned long indx, int size, int type, bool normalized,
+    unsigned long stride, unsigned long offset) {
+  makeContextCurrent();
+
+  if (bound_array_buffer_ <= 0) {
+    // FIXME: raise exception.
+    // LogMessagef(("bufferData: no buffer bound"));
+    return;
+  }
+
+  if (indx < kNumTrackedPointerStates) {
+    VertexAttribPointerState& state = vertex_attrib_pointer_state_[indx];
+    state.buffer = bound_array_buffer_;
+    state.indx = indx;
+    state.size = size;
+    state.type = type;
+    state.normalized = normalized;
+    state.stride = stride;
+    state.offset = offset;
+  }
+
+  glVertexAttribPointer(indx, size, type, normalized, stride,
+                        reinterpret_cast<void*>(static_cast<intptr_t>(offset)));
+}
+
+DELEGATE_TO_GL_4(viewport, Viewport, long, long, unsigned long, unsigned long)
+
+unsigned WebGraphicsContext3DInProcessImpl::createBuffer() {
+  makeContextCurrent();
+  GLuint o;
+  glGenBuffersARB(1, &o);
+  return o;
+}
+
+unsigned WebGraphicsContext3DInProcessImpl::createFramebuffer() {
+  makeContextCurrent();
+  GLuint o = 0;
+  glGenFramebuffersEXT(1, &o);
+  return o;
+}
+
+unsigned WebGraphicsContext3DInProcessImpl::createProgram() {
+  makeContextCurrent();
+  return glCreateProgram();
+}
+
+unsigned WebGraphicsContext3DInProcessImpl::createRenderbuffer() {
+  makeContextCurrent();
+  GLuint o;
+  glGenRenderbuffersEXT(1, &o);
+  return o;
+}
+
+unsigned WebGraphicsContext3DInProcessImpl::createShader(
+    unsigned long shaderType) {
+  makeContextCurrent();
+  DCHECK(shaderType == GL_VERTEX_SHADER || shaderType == GL_FRAGMENT_SHADER);
+  unsigned shader = glCreateShader(shaderType);
+  if (shader) {
+    ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+    if (result != shader_source_map_.end()) {
+      delete result->second;
+      shader_source_map_.erase(result);
+    }
+    shader_source_map_.insert(
+        ShaderSourceMap::value_type(shader, new ShaderSourceEntry(shaderType)));
+  }
+
+  return shader;
+}
+
+unsigned WebGraphicsContext3DInProcessImpl::createTexture() {
+  makeContextCurrent();
+  GLuint o;
+  glGenTextures(1, &o);
+  return o;
+}
+
+void WebGraphicsContext3DInProcessImpl::deleteBuffer(unsigned buffer) {
+  makeContextCurrent();
+  glDeleteBuffersARB(1, &buffer);
+}
+
+void WebGraphicsContext3DInProcessImpl::deleteFramebuffer(
+    unsigned framebuffer) {
+  makeContextCurrent();
+  glDeleteFramebuffersEXT(1, &framebuffer);
+}
+
+void WebGraphicsContext3DInProcessImpl::deleteProgram(unsigned program) {
+  makeContextCurrent();
+  glDeleteProgram(program);
+}
+
+void WebGraphicsContext3DInProcessImpl::deleteRenderbuffer(
+    unsigned renderbuffer) {
+  makeContextCurrent();
+  glDeleteRenderbuffersEXT(1, &renderbuffer);
+}
+
+void WebGraphicsContext3DInProcessImpl::deleteShader(unsigned shader) {
+  makeContextCurrent();
+
+  ShaderSourceMap::iterator result = shader_source_map_.find(shader);
+  if (result != shader_source_map_.end()) {
+    delete result->second;
+    shader_source_map_.erase(result);
+  }
+  glDeleteShader(shader);
+}
+
+void WebGraphicsContext3DInProcessImpl::deleteTexture(unsigned texture) {
+  makeContextCurrent();
+  glDeleteTextures(1, &texture);
+}
+
+bool WebGraphicsContext3DInProcessImpl::AngleCreateCompilers() {
+  if (!ShInitialize())
+    return false;
+
+  ShBuiltInResources resources;
+  ShInitBuiltInResources(&resources);
+  getIntegerv(GL_MAX_VERTEX_ATTRIBS, &resources.MaxVertexAttribs);
+  getIntegerv(MAX_VERTEX_UNIFORM_VECTORS, &resources.MaxVertexUniformVectors);
+  getIntegerv(MAX_VARYING_VECTORS, &resources.MaxVaryingVectors);
+  getIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS,
+              &resources.MaxVertexTextureImageUnits);
+  getIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS,
+              &resources.MaxCombinedTextureImageUnits);
+  getIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &resources.MaxTextureImageUnits);
+  getIntegerv(MAX_FRAGMENT_UNIFORM_VECTORS,
+              &resources.MaxFragmentUniformVectors);
+  // Always set to 1 for OpenGL ES.
+  resources.MaxDrawBuffers = 1;
+
+  fragment_compiler_ = ShConstructCompiler(
+      SH_FRAGMENT_SHADER, SH_WEBGL_SPEC, &resources);
+  vertex_compiler_ = ShConstructCompiler(
+      SH_VERTEX_SHADER, SH_WEBGL_SPEC, &resources);
+  return (fragment_compiler_ && vertex_compiler_);
+}
+
+void WebGraphicsContext3DInProcessImpl::AngleDestroyCompilers() {
+  if (fragment_compiler_) {
+    ShDestruct(fragment_compiler_);
+    fragment_compiler_ = 0;
+  }
+  if (vertex_compiler_) {
+    ShDestruct(vertex_compiler_);
+    vertex_compiler_ = 0;
+  }
+}
+
+bool WebGraphicsContext3DInProcessImpl::AngleValidateShaderSource(
+    ShaderSourceEntry* entry) {
+  entry->is_valid = false;
+  entry->translated_source.reset();
+  entry->log.reset();
+
+  ShHandle compiler = 0;
+  switch (entry->type) {
+    case GL_FRAGMENT_SHADER:
+      compiler = fragment_compiler_;
+      break;
+    case GL_VERTEX_SHADER:
+      compiler = vertex_compiler_;
+      break;
+  }
+  if (!compiler)
+    return false;
+
+  char* source = entry->source.get();
+  if (!ShCompile(compiler, &source, 1, SH_OBJECT_CODE)) {
+    int logSize = 0;
+    ShGetInfo(compiler, SH_INFO_LOG_LENGTH, &logSize);
+    if (logSize > 1) {
+      entry->log.reset(new char[logSize]);
+      ShGetInfoLog(compiler, entry->log.get());
+    }
+    return false;
+  }
+
+  int length = 0;
+  if (is_gles2_) {
+    // ANGLE does not yet have a GLSL ES backend. Therefore if the
+    // compile succeeds we send the original source down.
+    length = strlen(entry->source.get());
+    if (length > 0)
+      ++length;  // Add null terminator
+  } else {
+    ShGetInfo(compiler, SH_OBJECT_CODE_LENGTH, &length);
+  }
+  if (length > 1) {
+    entry->translated_source.reset(new char[length]);
+    if (is_gles2_)
+      strncpy(entry->translated_source.get(), entry->source.get(), length);
+    else
+      ShGetObjectCode(compiler, entry->translated_source.get());
+  }
+  entry->is_valid = true;
+  return true;
+}
+
+}  // namespace webkit_gpu
+