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 1d642fd1d16cc08c26481deb1f9100971493ddb9..1ca26dcba7aa951879e3fa9d110b1f93e1e23ca2 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -627,6 +627,8 @@ class GLES2DecoderImpl : public GLES2Decoder {
     return vertex_array_manager_.get();
   }
   virtual bool ProcessPendingQueries() OVERRIDE;
+  virtual bool HasMoreIdleWork() OVERRIDE;
+  virtual void PerformIdleWork() OVERRIDE;
 
   virtual void SetResizeCallback(
       const base::Callback<void(gfx::Size)>& callback) OVERRIDE;
@@ -9245,6 +9247,17 @@ bool GLES2DecoderImpl::ProcessPendingQueries() {
   return query_manager_->HavePendingQueries();
 }
 
+bool GLES2DecoderImpl::HasMoreIdleWork() {
+  return async_pixel_transfer_delegate_->NeedsProcessPendingTransfers();
+}
+
+void GLES2DecoderImpl::PerformIdleWork() {
+  if (!async_pixel_transfer_delegate_->NeedsProcessPendingTransfers())
+    return;
+  async_pixel_transfer_delegate_->ProcessPendingTransfers();
+  ProcessFinishedAsyncTransfers();
+}
+
 error::Error GLES2DecoderImpl::HandleBeginQueryEXT(
     uint32 immediate_data_size, const cmds::BeginQueryEXT& c) {
   GLenum target = static_cast<GLenum>(c.target);