Add initial GpuMemoryBufferSurfaceTexture implementation.

ui/gl/gl_image_surface_texture.cc

+// Copyright 2014 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 "ui/gl/gl_image_surface_texture.h"
+
+#include "base/debug/trace_event.h"
+#include "ui/gl/android/surface_texture.h"
+#include "ui/gl/android/surface_texture_tracker.h"
+#include "ui/gl/gl_bindings.h"
+
+namespace gfx {
+namespace {
+
+// This is admittedly a bit ugly. SurfaceTexture API takes ownership of texture
+// ids when AttachToGLContext() is called and will delete the texture unless
+// DetachFromGLContext() is called with no context current. This helper class
+// can be used to temporarily make no context current for the purpose of
+// stealing the texture id of a given surface texture.
+class ScopedNoContextCurrent {
+ public:
+  ScopedNoContextCurrent()
+      : display_(eglGetCurrentDisplay()),
+        context_(eglGetCurrentContext()),
+        draw_surface_(eglGetCurrentSurface(EGL_DRAW)),
+        read_surface_(eglGetCurrentSurface(EGL_READ)) {
+    eglMakeCurrent(display_, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+  }
+
+  ~ScopedNoContextCurrent() {
+    eglMakeCurrent(display_, draw_surface_, read_surface_, context_);
+  }
+
+ private:
+  EGLDisplay display_;
+  EGLContext context_;
+  EGLSurface draw_surface_;
+  EGLSurface read_surface_;
+};
+
+void DetachFromGLContext(SurfaceTexture* surface_texture) {
+  // Detach with no context current to prevent SurfaceTexture from deleting
+  // currently attached texture id.
+  ScopedNoContextCurrent no_context_current;
+  surface_texture->DetachFromGLContext();
+}
+
+}  // namespace
+
+GLImageSurfaceTexture::GLImageSurfaceTexture(gfx::Size size)
+    : size_(size), texture_id_(0) {}
+
+GLImageSurfaceTexture::~GLImageSurfaceTexture() { Destroy(); }
+
+bool GLImageSurfaceTexture::Initialize(gfx::GpuMemoryBufferHandle buffer) {
+  DCHECK(!surface_texture_);
+  surface_texture_ =
+      SurfaceTextureTracker::GetInstance()->AcquireSurfaceTexture(
+          buffer.surface_texture_id.primary_id,
+          buffer.surface_texture_id.secondary_id);
+  return !!surface_texture_;
+}
+
+void GLImageSurfaceTexture::Destroy() {
+  surface_texture_ = NULL;
+  texture_id_ = 0;
+}
+
+gfx::Size GLImageSurfaceTexture::GetSize() { return size_; }
+
+bool GLImageSurfaceTexture::BindTexImage(unsigned target) {
+  TRACE_EVENT0("gpu", "GLImageSurfaceTexture::BindTexImage");
+
+  if (target != GL_TEXTURE_EXTERNAL_OES) {
+    LOG(ERROR)
+        << "Surface texture can only be bound to TEXTURE_EXTERNAL_OES target";
+    return false;
+  }
+
+  int texture_id;
+  glGetIntegerv(GL_TEXTURE_BINDING_EXTERNAL_OES, &texture_id);
+  DCHECK(texture_id);
+
+  if (texture_id_ && texture_id_ != texture_id) {
+    LOG(ERROR) << "Surface texture can only be bound to one texture ID";
+    return false;
+  }
+
+  DCHECK(surface_texture_);
+  if (texture_id != texture_id_) {
+    DetachFromGLContext(surface_texture_.get());
+    surface_texture_->AttachToGLContext();
+    texture_id_ = texture_id;
+  }
+
+  surface_texture_->UpdateTexImage();
+  return true;
+}
+
+}  // namespace gfx