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

mojo/gles2/command_buffer_client_impl.h

Index: mojo/gles2/command_buffer_client_impl.h
diff --git a/mojo/gles2/command_buffer_client_impl.h b/mojo/gles2/command_buffer_client_impl.h
index c1e4231ce07ef441bcdd2cea5501fdd837edf316..a0d0cd7bc9fbe5f8c80309d96e5c79e8ee0409e0 100644
--- a/mojo/gles2/command_buffer_client_impl.h
+++ b/mojo/gles2/command_buffer_client_impl.h
@@ -76,10 +76,12 @@ class CommandBufferClientImpl
   bool IsGpuChannelLost() override;
   gpu::CommandBufferNamespace GetNamespaceID() const override;
   uint64_t GetCommandBufferID() const override;
+  uint32_t GetExtraCommandBufferData() const override;
   uint64_t GenerateFenceSyncRelease() override;
   bool IsFenceSyncRelease(uint64_t release) override;
   bool IsFenceSyncFlushed(uint64_t release) override;
   bool IsFenceSyncFlushReceived(uint64_t release) override;
+
   void SignalSyncToken(const gpu::SyncToken& sync_token,
                        const base::Closure& callback) override;
   bool CanWaitUnverifiedSyncToken(const gpu::SyncToken* sync_token) override;