Early wait on texture resource sync points in gl_renderer.

cc/output/direct_renderer.cc

Index: cc/output/direct_renderer.cc
diff --git a/cc/output/direct_renderer.cc b/cc/output/direct_renderer.cc
index be5d2bff5be469716352781daae22a622c48d4ed..c2c8aff3986994529c93e62b8c702e780ef1886a 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -56,6 +56,13 @@ static gfx::Transform window_matrix(int x, int y, int width, int height) {
 
 namespace cc {
 
+static ResourceProvider::ResourceId WaitOnResourceSyncPoints(
+    ResourceProvider* resource_provider,
+    ResourceProvider::ResourceId resource_id) {
+  resource_provider->WaitSyncPointIfNeeded(resource_id);
+  return resource_id;
+}
+
 DirectRenderer::DrawingFrame::DrawingFrame()
     : root_render_pass(NULL), current_render_pass(NULL), current_texture(NULL) {
 }
@@ -225,6 +232,20 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
   // viewport size is never set.
   output_surface_->Reshape(device_viewport_rect.size(), device_scale_factor);
 
+  // Insert WaitSyncPointCHROMIUM on quad resources prior to drawing the frame,
+  // so that drawing can proceed without GL context switching interruptions.
+  // crbug.com/394547

[danakj, 2014/08/13 23:05:19]

git blame will point to the bug, i think you can drop this from the comment

[vmiura, 2014/08/15 21:20:39]

Done.

+  DrawQuad::ResourceIteratorCallback wait_on_resource_syncpoints_callback =
+      base::Bind(&WaitOnResourceSyncPoints, resource_provider_);
+
+  for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
+    RenderPass* pass = render_passes_in_draw_order->at(i);
+    for (size_t j = 0; j < pass->quad_list.size(); ++j) {
+      DrawQuad* quad = pass->quad_list[j];
+      quad->IterateResources(wait_on_resource_syncpoints_callback);
+    }
+  }
+
   BeginDrawingFrame(&frame);
   for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
     RenderPass* pass = render_passes_in_draw_order->at(i);