Added a unique command buffer ID for command buffers.

content/common/gpu/client/command_buffer_proxy_impl.cc

Index: content/common/gpu/client/command_buffer_proxy_impl.cc
diff --git a/content/common/gpu/client/command_buffer_proxy_impl.cc b/content/common/gpu/client/command_buffer_proxy_impl.cc
index 53ce2d7ee543787639fe8e1d0d14af7e50d20764..ae516abf240a66e9f6cd1e901bb182a81ccdce87 100644
--- a/content/common/gpu/client/command_buffer_proxy_impl.cc
+++ b/content/common/gpu/client/command_buffer_proxy_impl.cc
@@ -27,10 +27,16 @@
 
 namespace content {
 
+uint64_t CommandBufferProxyID(int channel_id, int32 route_id) {
+  return (static_cast<uint64_t>(channel_id) << 32) | route_id;
+}
+
 CommandBufferProxyImpl::CommandBufferProxyImpl(GpuChannelHost* channel,
                                                int32 route_id,
                                                int32 stream_id)
-    : lock_(nullptr),
+    : CommandBuffer(gpu::kCommandBufferNamespace_GpuIO,
+                    CommandBufferProxyID(channel->channel_id(), route_id)),
+      lock_(nullptr),
       channel_(channel),
       route_id_(route_id),
       stream_id_(stream_id),