Use TimeTicks instead of clock() in gpu::CommandBufferHelper

gpu/command_buffer/client/cmd_buffer_helper.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains the command buffer helper class.
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_
 #define GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_
 
 #include <string.h>
@@ skipping 307 matching lines @@
   int32 last_put_sent_;
 
 #if defined(CMD_HELPER_PERIODIC_FLUSH_CHECK)
   int commands_issued_;
 #endif
 
   bool usable_;
   bool context_lost_;
   bool flush_automatically_;
 
-  // Using C runtime instead of base because this file cannot depend on base.
-  clock_t last_flush_time_;
+  // Using primitive type instead of base::TimeTicks because this file

[hamaji, 2014/07/09 06:03:15]

Is this comment right? It seems other header files in this directory #include
base headers.

For now, I declared this as int64 assuming this comment is right.

[piman, 2014/07/09 20:13:46]

This used to be true because of NaCl, but now it should be ok to depend on base
(we've been progressively fixing headers to that effect).

[hamaji, 2014/07/10 07:00:16]

Good news! Now I removed the comment and changed clock_t to TimeTicks.

+  // cannot depend on base.
+  int64 last_flush_time_;
 
   // Incremented every time the helper flushes the command buffer.
   // Can be used to track when prior commands have been flushed.
   uint32 flush_generation_;
 
   friend class CommandBufferHelperTest;
   DISALLOW_COPY_AND_ASSIGN(CommandBufferHelper);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_