Enable partial texture upload support for browser compositor with Surfaces

content/browser/compositor/surface_display_output_surface.cc

Index: content/browser/compositor/surface_display_output_surface.cc
diff --git a/content/browser/compositor/surface_display_output_surface.cc b/content/browser/compositor/surface_display_output_surface.cc
index f80d14f76dc5f3805cff765899f9c1a8c75ad296..f0959b8d41806204c126174f3956c6f1d2d39c2c 100644
--- a/content/browser/compositor/surface_display_output_surface.cc
+++ b/content/browser/compositor/surface_display_output_surface.cc
@@ -25,6 +25,7 @@ SurfaceDisplayOutputSurface::SurfaceDisplayOutputSurface(
       allocator_(allocator) {
   capabilities_.delegated_rendering = true;
   capabilities_.max_frames_pending = 1;
+  capabilities_.can_force_reclaim_resources = true;
 }
 
 SurfaceDisplayOutputSurface::~SurfaceDisplayOutputSurface() {
@@ -75,6 +76,15 @@ bool SurfaceDisplayOutputSurface::BindToClient(
   return display_client_->Initialize();
 }
 
+void SurfaceDisplayOutputSurface::ForceReclaimResources() {
+  if (!surface_id_.is_null()) {
+    scoped_ptr<cc::CompositorFrame> frame_copy(new cc::CompositorFrame());

[jamesr, 2015/01/09 01:14:45]

what is this a copy of? this looks more like a completely empty frame

+    frame_copy->delegated_frame_data.reset(new cc::DelegatedFrameData);
+    factory_.SubmitFrame(surface_id_, frame_copy.Pass(),
+                         cc::SurfaceFactory::DrawCallback());
+  }
+}
+
 void SurfaceDisplayOutputSurface::ReturnResources(
     const cc::ReturnedResourceArray& resources) {
   cc::CompositorFrameAck ack;