Added a unique command buffer ID for command buffers.

ppapi/proxy/ppapi_command_buffer_proxy.cc

Index: ppapi/proxy/ppapi_command_buffer_proxy.cc
diff --git a/ppapi/proxy/ppapi_command_buffer_proxy.cc b/ppapi/proxy/ppapi_command_buffer_proxy.cc
index 7a42524bff2fe2827ffbce153f9d62f1a011b108..e8e094272a7b1130d0796b3f6051d1746e264702 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.cc
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.cc
@@ -177,6 +177,16 @@ bool PpapiCommandBufferProxy::IsGpuChannelLost() {
   return false;
 }
 
+gpu::CommandBufferNamespace PpapiCommandBufferProxy::GetNamespaceID() const {
+  NOTIMPLEMENTED();
+  return gpu::kCommandBufferNamespace_Invalid;
+}
+
+uint64_t PpapiCommandBufferProxy::GetCommandBufferID() const {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
 uint32 PpapiCommandBufferProxy::InsertSyncPoint() {
   uint32 sync_point = 0;
   if (last_state_.error == gpu::error::kNoError) {