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..ef273737c32a0cd09ff04033b77247ce6313dd2e 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -41,6 +41,7 @@
 #include "cc/quads/stream_video_draw_quad.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "cc/raster/scoped_gpu_raster.h"
+#include "cc/resources/resource_pool.h"
 #include "cc/resources/scoped_resource.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/context_support.h"
@@ -371,6 +372,11 @@ GLRenderer::GLRenderer(RendererClient* client,
       context_caps.blend_equation_advanced_coherent;
 
   InitializeSharedObjects();
+
+  // TODO(erikchen): Fix this to allow the creation of IOSurfaces.
+  // https://crbug.com/581526.
+  overlay_resource_pool_ = ResourcePool::CreateForGpuMemoryBufferResources(
+      resource_provider_, nullptr);
 }
 
 GLRenderer::~GLRenderer() {
@@ -2796,7 +2802,7 @@ 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);
     }
   }
 }
@@ -3631,12 +3637,23 @@ bool GLRenderer::IsContextLost() {
 }
 
 void GLRenderer::ScheduleCALayers(DrawingFrame* frame) {
+  size_t copied_render_pass_count = 0;
   for (const CALayerOverlay& ca_layer_overlay : frame->ca_layer_overlay_list) {

[ccameron, 2016/07/21 05:31:16]

Resource* overlay_resource = nullptr;

+    ResourceId contents_resource_id = ca_layer_overlay.contents_resource_id;
+    // Some CALayers require a final round of processing.
+    if (ca_layer_overlay.render_pass_id.IsValid()) {
+      ResourceId resource_id;
+      CopyRenderPassToOverlayResource(ca_layer_overlay.render_pass_id,
+                                      &resource_id);

[ccameron, 2016/07/21 05:31:16]

CopyRenderPassToOverlayResource now takes a Resource**, &overlay_resource.

+      contents_resource_id = resource_id;
+      ++copied_render_pass_count;
+    }
+
     unsigned texture_id = 0;
-    if (ca_layer_overlay.contents_resource_id) {
+    if (contents_resource_id) {
       pending_overlay_resources_.push_back(
           base::WrapUnique(new ResourceProvider::ScopedReadLockGL(
-              resource_provider_, ca_layer_overlay.contents_resource_id)));
+              resource_provider_, contents_resource_id)));
       texture_id = pending_overlay_resources_.back()->texture_id();
     }

[ccameron, 2016/07/21 05:31:16]

At this point it's safe to
if (overlay_resource)
  overlay_resource_pool_->ReleaseResource(overlay_resource)
because we have the lock, which will prevent the pool from re-using it.

We could, alternatively, save up a vector of Resource*s, and release them all at
the end, if that seems better.

     GLfloat contents_rect[4] = {
@@ -3665,6 +3682,11 @@ void GLRenderer::ScheduleCALayers(DrawingFrame* frame) {
         bounds_rect, is_clipped, clip_rect, sorting_context_id, transform,
         filter);
   }
+
+  // Take the number of copied render passes in this frame, and use 3 times that
+  // amount as the cache limit.
+  overlay_resource_pool_->SetResourceUsageLimits(
+      std::numeric_limits<std::size_t>::max(), copied_render_pass_count * 3);
 }
 
 void GLRenderer::ScheduleOverlays(DrawingFrame* frame) {
@@ -3690,4 +3712,41 @@ void GLRenderer::ScheduleOverlays(DrawingFrame* frame) {
   }
 }
 
+void GLRenderer::OverlayResourceNoLongerInUse(GLuint texture) {
+  auto it = swapped_and_acked_overlay_resources_.find(texture);
+  if (it != swapped_and_acked_overlay_resources_.end()) {
+    overlay_resource_pool_->ReleaseResourceIfFound(it->second->resource_id());
+    swapped_and_acked_overlay_resources_.erase(it);

[ccameron, 2016/07/20 22:13:53]

(from gl_renderer.h) ... 

We can just check for resource_id in overlay_pool_resources_in_use_, and release
it back to the pool if we find it.

[erikchen, 2016/07/20 23:40:39]

I don't think that's a great idea. We'd be maintaining a copy of the member
|in_use_resources_| of resource pool, using separate logic, just so that we
could check whether a given resource is in the data structure.

[ccameron, 2016/07/21 05:31:16]

This would now no longer need to do the release.

+  }
+}
+
+void GLRenderer::CopyRenderPassToOverlayResource(
+    const RenderPassId& render_pass_id,
+    ResourceId* resource_id) {
+  ScopedResource* contents_texture =
+      render_pass_textures_[render_pass_id].get();
+  DCHECK(contents_texture);
+  DCHECK(contents_texture->id());
+  Resource* resource = overlay_resource_pool_->AcquireResource(
+      contents_texture->size(), ResourceFormat::RGBA_8888);
+  *resource_id = resource->id();
+  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);
+}
+
 }  // namespace cc