gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/cmd_buffer_helper.h

Index: gpu/command_buffer/client/cmd_buffer_helper.h
diff --git a/gpu/command_buffer/client/cmd_buffer_helper.h b/gpu/command_buffer/client/cmd_buffer_helper.h
index a50dc7bfe4e4e73e4bc4ce392bc1cb85e32182be..7ee6a3f7c01dd7a35bb57ba936c4befc4492529c 100644
--- a/gpu/command_buffer/client/cmd_buffer_helper.h
+++ b/gpu/command_buffer/client/cmd_buffer_helper.h
@@ -83,6 +83,11 @@ class GPU_EXPORT CommandBufferHelper {
   //   shutdown.
   int32 InsertToken();
 
+  // Returns true if the token has already passed.
+  // Parameters:
+  //   the value of the token to check whether it has passed
+  bool HasTokenPassed(int32 token);

[reveman, 2014/01/02 01:31:29]

why is this needed in addition to last_token_read()?

[jadahl, 2014/01/02 10:59:54]

No need. Will remove. No idea why I added it herein the first place :P

[epennerAtGoogle, 2014/01/07 00:47:59]

Just FYI, I actually like this (as an inline function though). Even minor
reductions in logic makes code more clear and less likely to have bugs.

+
   // Waits until the token of a particular value has passed through the command
   // stream (i.e. commands inserted before that token have been executed).
   // NOTE: This will call Flush if it needs to block.