Add logic to GLRenderer to support RenderPassDrawQuad copying.

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 9456c005c2e19dd4f111a81a4984a05e9d31dc65..66d67121695aec6b070388cdd4327d50d4ab9d37 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -2796,7 +2796,7 @@ void GLRenderer::DidReceiveTextureInUseResponses(
   DCHECK(settings_->release_overlay_resources_after_gpu_query);
   for (const gpu::TextureInUseResponse& response : responses) {
     if (!response.in_use) {
-      swapped_and_acked_overlay_resources_.erase(response.texture);
+      OverlayResourceNoLongerInUse(response.texture);
     }
   }
 }
@@ -3690,4 +3690,94 @@ void GLRenderer::ScheduleOverlays(DrawingFrame* frame) {
   }
 }
 
+void GLRenderer::OverlayResourceNoLongerInUse(GLuint texture) {
+  auto it = swapped_and_acked_overlay_resources_.find(texture);
+  std::vector<ResourceId> resource_ids;
+  if (it != swapped_and_acked_overlay_resources_.end()) {
+    resource_ids.push_back(it->second->resource_id());
+    swapped_and_acked_overlay_resources_.erase(it);
+  }
+  ReleaseIOSurfaces(resource_ids);
+}
+
+ResourceId GLRenderer::CreateOrReuseIOSurface(const gfx::Size& size) {
+  DCHECK(settings_->release_overlay_resources_after_gpu_query);
+  for (auto it = free_iosurfaces_.begin(); it != free_iosurfaces_.end(); ++it) {
+    if ((*it)->size() == size) {
+      ResourceId id = (*it)->id();
+      in_use_iosurfaces_.emplace_back(std::move(*it));
+      free_iosurfaces_.erase(it);
+      return id;
+    }
+  }
+
+  // TODO(erikchen): Update ScopedResouce to support IOSurface creation. This
+  // code doesn't actually make an IOSurface. https://crbug.com/581526.
+  std::unique_ptr<ScopedResource> resource =
+      ScopedResource::Create(resource_provider_);
+  resource->AllocateWithGpuMemoryBuffer(size, ResourceFormat::RGBA_8888);
+  ResourceId id = resource->id();
+  in_use_iosurfaces_.emplace_back(std::move(resource));
+  return id;
+}
+
+void GLRenderer::DeleteIOSurfacesOverCacheLimit() {
+  if (free_iosurfaces_.size() > iosurface_limit_) {
+    size_t num_to_erase = free_iosurfaces_.size() - iosurface_limit_;
+    free_iosurfaces_.erase(free_iosurfaces_.begin(),
+                           free_iosurfaces_.begin() + num_to_erase);
+  }
+}
+
+bool GLRenderer::CopyRenderPassDrawQuadToIOSurface(
+    const RenderPassDrawQuad* quad,
+    ResourceId* resource_id) {
+  ScopedResource* contents_texture =
+      render_pass_textures_[quad->render_pass_id].get();
+  DCHECK(contents_texture);
+  DCHECK(contents_texture->id());
+  *resource_id = CreateOrReuseIOSurface(contents_texture->size());
+  ResourceProvider::ScopedWriteLockGL destination(resource_provider_,
+                                                  *resource_id, false);
+
+  GLuint source_texture = 0;
+  std::unique_ptr<ResourceProvider::ScopedReadLockGL> source;
+  if (current_framebuffer_lock_ &&
+      current_framebuffer_lock_->texture_id() == contents_texture->id()) {
+    source_texture = current_framebuffer_lock_->texture_id();
+  } else {
+    source.reset(new ResourceProvider::ScopedReadLockGL(
+        resource_provider_, contents_texture->id()));
+    source_texture = source->texture_id();
+  }
+  gl_->CopySubTextureCHROMIUM(source_texture, destination.texture_id(), 0, 0, 0,
+                              0, contents_texture->size().width(),
+                              contents_texture->size().height(), GL_TRUE,
+                              GL_FALSE, GL_FALSE);
+  return true;
+}
+
+void GLRenderer::ReleaseIOSurfaces(const std::vector<ResourceId>& resources) {
+  if (in_use_iosurfaces_.empty() || resources.empty())
+    return;
+
+  // Move all IOSurfaces that match resources to the end of in_use_iosurfaces_.
+  for (auto it = in_use_iosurfaces_.rbegin(); it != in_use_iosurfaces_.rend();
+       ++it) {
+    if (std::find(resources.begin(), resources.end(), (*it)->id()) !=
+        resources.end()) {
+      free_iosurfaces_.emplace_back(std::move(*it));
+      in_use_iosurfaces_.erase(std::next(it).base());
+    }
+  }
+
+  DeleteIOSurfacesOverCacheLimit();
+}
+
+void GLRenderer::UpdateCopyCountForFrame(size_t count) {
+  // Keep two frames worth of cached IOSurfaces.
+  iosurface_limit_ = count * 2;
+  DeleteIOSurfacesOverCacheLimit();
+}
+
 }  // namespace cc