Impl mus::mojom::GpuService to enable using Chrome IPC version gpu CmdBuf in mus

components/mus/public/cpp/context_provider.h

Index: components/mus/public/cpp/context_provider.h
diff --git a/components/mus/public/cpp/context_provider.h b/components/mus/public/cpp/context_provider.h
index 78d701bf8a327e9734f5181c24e81055d68bd542..8a5eb97249b0227de5a229073ec07a01a034dd12 100644
--- a/components/mus/public/cpp/context_provider.h
+++ b/components/mus/public/cpp/context_provider.h
@@ -11,13 +11,14 @@
 
 #include "base/macros.h"
 #include "cc/output/context_provider.h"
+#include "components/mus/public/cpp/mus_public_export.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace mus {
 
 class GLES2Context;
 
-class ContextProvider : public cc::ContextProvider {
+class MUS_PUBLIC_EXPORT ContextProvider : public cc::ContextProvider {
  public:
   explicit ContextProvider(mojo::ScopedMessagePipeHandle command_buffer_handle);