Added a unique command buffer ID for command buffers.

content/common/gpu/gpu_command_buffer_stub.cc

Index: content/common/gpu/gpu_command_buffer_stub.cc
diff --git a/content/common/gpu/gpu_command_buffer_stub.cc b/content/common/gpu/gpu_command_buffer_stub.cc
index d91a65259efff40f2100f525e8bcab7dd98e8555..c028e3248549b77596cf4c7ae55a08c226d9a4f7 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -488,7 +488,9 @@ void GpuCommandBufferStub::OnInitialize(
       new base::SharedMemory(shared_state_handle, false));
 
   command_buffer_.reset(new gpu::CommandBufferService(
-      context_group_->transfer_buffer_manager()));
+      context_group_->transfer_buffer_manager(),
+      gpu::kCommandBufferNamespace_GpuIO,
+      (static_cast<uint64_t>(channel_->client_id()) << 32) | route_id_));
 
   bool result = command_buffer_->Initialize();
   DCHECK(result);