Added an extra sync token field for extra command buffer identification.

content/common/gpu/client/gpu_channel_host.cc

Index: content/common/gpu/client/gpu_channel_host.cc
diff --git a/content/common/gpu/client/gpu_channel_host.cc b/content/common/gpu/client/gpu_channel_host.cc
index 80dfe0a48a074fe5ecd3040dd6a5c9e2361922f6..805256324ab46a3cfb774ef3e60b8e895b70c47d 100644
--- a/content/common/gpu/client/gpu_channel_host.cc
+++ b/content/common/gpu/client/gpu_channel_host.cc
@@ -162,6 +162,13 @@ uint32_t GpuChannelHost::OrderingBarrier(
   return 0;
 }
 
+void GpuChannelHost::FlushPendingStream(int32 stream_id) {
+  AutoLock lock(context_lock_);
+  StreamFlushInfo& flush_info = stream_flush_info_[stream_id];
+  if (flush_info.flush_pending)
+    InternalFlush(&flush_info);
+}
+
 void GpuChannelHost::InternalFlush(StreamFlushInfo* flush_info) {
   context_lock_.AssertAcquired();
   DCHECK(flush_info);