Introducing gpu::CommandBufferId as a distinct, IdType<...>-based type.

content/common/gpu/client/command_buffer_proxy_impl.h

Index: content/common/gpu/client/command_buffer_proxy_impl.h
diff --git a/content/common/gpu/client/command_buffer_proxy_impl.h b/content/common/gpu/client/command_buffer_proxy_impl.h
index 2f0ed90e17f9a923e5dc67323485f684944967b3..5de26f52dca92f7a60ee9b6f220979da9c42cb94 100644
--- a/content/common/gpu/client/command_buffer_proxy_impl.h
+++ b/content/common/gpu/client/command_buffer_proxy_impl.h
@@ -22,6 +22,7 @@
 #include "base/observer_list.h"
 #include "gpu/command_buffer/client/gpu_control.h"
 #include "gpu/command_buffer/common/command_buffer.h"
+#include "gpu/command_buffer/common/command_buffer_id.h"
 #include "gpu/command_buffer/common/command_buffer_shared.h"
 #include "gpu/command_buffer/common/gpu_memory_allocation.h"
 #include "ipc/ipc_listener.h"
@@ -121,7 +122,7 @@ class CommandBufferProxyImpl
   bool IsGpuChannelLost() override;
   void EnsureWorkVisible() override;
   gpu::CommandBufferNamespace GetNamespaceID() const override;
-  uint64_t GetCommandBufferID() const override;
+  gpu::CommandBufferId GetCommandBufferID() const override;
   int32_t GetExtraCommandBufferData() const override;
   uint64_t GenerateFenceSyncRelease() override;
   bool IsFenceSyncRelease(uint64_t release) override;
@@ -229,7 +230,7 @@ class CommandBufferProxyImpl
   // |*this| is owned by |*channel_| and so is always outlived by it, so using a
   // raw pointer is ok.
   GpuChannelHost* channel_;
-  const uint64_t command_buffer_id_;
+  const gpu::CommandBufferId command_buffer_id_;
   const int32_t route_id_;
   const int32_t stream_id_;
   uint32_t flush_count_;