gpu: Implement idle async pixel transfers.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 8b183c06009e991c2d500ad5871c83b9bf3e7fb6..ea6686c9b9c6f5e4979317b6a2c6d46507229a11 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -572,6 +572,8 @@ class GLES2DecoderImpl : public GLES2Decoder {
     return vertex_array_manager_.get();
   }
   virtual bool ProcessPendingQueries() OVERRIDE;
+  virtual bool HasMoreWork() OVERRIDE;
+  virtual bool PerformIdleWork() OVERRIDE;
 
   virtual void SetResizeCallback(
       const base::Callback<void(gfx::Size)>& callback) OVERRIDE;
@@ -9094,6 +9096,17 @@ bool GLES2DecoderImpl::ProcessPendingQueries() {
   return query_manager_->HavePendingQueries();
 }
 
+bool GLES2DecoderImpl::HasMoreWork() {
+  return ProcessPendingQueries() ||
+      async_pixel_transfer_delegate_->HasPendingTransfers();
+}
+
+bool GLES2DecoderImpl::PerformIdleWork() {
+  async_pixel_transfer_delegate_->ProcessPendingTransfers();
+  RestoreCurrentTexture2DBindings();

[Sami, 2013/03/07 16:57:19]

Maybe only restore the bindings only if we actually did something -- that is if
we can get here without any pending transfers.

[reveman, 2013/03/07 20:21:04]

Done.

+  return async_pixel_transfer_delegate_->HasPendingTransfers();
+}
+
 error::Error GLES2DecoderImpl::HandleBeginQueryEXT(
     uint32 immediate_data_size, const cmds::BeginQueryEXT& c) {
   GLenum target = static_cast<GLenum>(c.target);