gpu: Reuse transfer buffers more aggresively

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 25509d8d7ee346ae696b01c6302758a7ad86447d..ea02fab1937b14e1b360fc9d0cdef5dbe7a38793 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -676,6 +676,12 @@ class GLES2DecoderImpl : public GLES2Decoder,
   bool GenVertexArraysOESHelper(GLsizei n, const GLuint* client_ids);
   void DeleteVertexArraysOESHelper(GLsizei n, const GLuint* client_ids);
 
+  // Callback for completed async uploads.
+  void AsyncUploadCompleted(uint32 async_token);

[reveman, 2014/01/22 17:30:04]

This is not really a completed upload, it's the passing of a token.
s/AsyncUploadCompleted/OnAsyncTokenPassed/ ?

+
+  // Overridden from CommonDecoder
+  virtual void OnSetAsyncToken(uint32 async_token) OVERRIDE;
+
   // Workarounds
   void OnFboChanged() const;
   void OnUseFramebuffer() const;
@@ -3547,6 +3553,17 @@ const char* GLES2DecoderImpl::GetCommandName(unsigned int command_id) const {
   return GetCommonCommandName(static_cast<cmd::CommandId>(command_id));
 }
 
+void GLES2DecoderImpl::AsyncUploadCompleted(uint32 async_token) {
+  engine()->set_async_token(async_token);
+}
+
+void GLES2DecoderImpl::OnSetAsyncToken(uint32 async_token) {
+  GetAsyncPixelTransferManager()->AsyncRunWhenCompleted(
+      base::Bind(&GLES2DecoderImpl::AsyncUploadCompleted,
+                 base::Unretained(this),
+                 async_token));
+}
+
 // Decode command with its arguments, and call the corresponding GL function.
 // Note: args is a pointer to the command buffer. As such, it could be changed
 // by a (malicious) client at any time, so if validation has to happen, it