Add OrderingBarrierCHROMIUM API.

gpu/command_buffer/client/cmd_buffer_helper.cc

 // 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 implementation of the command buffer helper class.
 
 #include "gpu/command_buffer/client/cmd_buffer_helper.h"
 
 #include "base/logging.h"
 #include "base/time/time.h"
@@ skipping 132 matching lines @@
   }
   command_buffer_->WaitForGetOffsetInRange(start, end);
   return command_buffer_->GetLastError() == gpu::error::kNoError;
 }
 
 void CommandBufferHelper::Flush() {
   // Wrap put_ before flush.
   if (put_ == total_entry_count_)
     put_ = 0;
 
-  if (usable() && last_put_sent_ != put_) {
+  if (usable()) {
     last_flush_time_ = base::TimeTicks::Now();
     last_put_sent_ = put_;
     command_buffer_->Flush(put_);
     ++flush_generation_;
     CalcImmediateEntries(0);
   }
 }
 
+void CommandBufferHelper::OrderingBarrier() {
+  // Wrap put_ before setting the barrier.
+  if (put_ == total_entry_count_)
+    put_ = 0;
+
+  if (usable()) {
+    command_buffer_->OrderingBarrier(put_);
+    ++flush_generation_;
+    CalcImmediateEntries(0);
+  }
+}
+
 #if defined(CMD_HELPER_PERIODIC_FLUSH_CHECK)
 void CommandBufferHelper::PeriodicFlushCheck() {
   base::TimeTicks current_time = base::TimeTicks::Now();
   if (current_time - last_flush_time_ >
       base::TimeDelta::FromMicroseconds(kPeriodicFlushDelayInMicroseconds)) {
     Flush();
   }
 }
 #endif
 
@@ skipping 112 matching lines @@
       if (!WaitForGetOffsetInRange(put_ + count + 1, put_))
         return;
       CalcImmediateEntries(count);
       DCHECK_GE(immediate_entry_count_, count);
     }
   }
 }
 
 
 }  // namespace gpu