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"
+
+namespace gfx {
+
+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;
+  }
+
+  GLint 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_) {
+    // Note: Surface textures used as gpu memory buffers are created with an
+    // initial dummy texture id of 0. We need to call DetachFromGLContext() here
+    // to detach from the dummy texture before we can attach to a real texture
+    // id. DetachFromGLContext() will delete the texture for the current
+    // attachment point so it's important that this is never called when
+    // attached to a real texture id. Detaching from the dummy texture id should
+    // not cause any problems as the GL should silently ignore 0 when passed to
+    // glDeleteTextures.
+    DCHECK_EQ(0, texture_id_);
+    surface_texture_->DetachFromGLContext();
+
+    // This will attach the surface texture to the texture currently bound to
+    // GL_TEXTURE_EXTERNAL_OES target.
+    surface_texture_->AttachToGLContext();
+    texture_id_ = texture_id;
+  }
+
+  surface_texture_->UpdateTexImage();
+  return true;
+}
+
+}  // namespace gfx