Consolidate OutputSurface constructors into GL vs Vulkan.

blimp/client/feature/compositor/blimp_output_surface.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BLIMP_CLIENT_FEATURE_COMPOSITOR_BLIMP_OUTPUT_SURFACE_H_
 #define BLIMP_CLIENT_FEATURE_COMPOSITOR_BLIMP_OUTPUT_SURFACE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "cc/output/output_surface.h"
 
 namespace blimp {
 namespace client {
 
 // Minimal implementation of cc::OutputSurface.
 class BlimpOutputSurface : public cc::OutputSurface {
  public:
   explicit BlimpOutputSurface(
-      const scoped_refptr<cc::ContextProvider>& context_provider);
+      scoped_refptr<cc::ContextProvider> context_provider);
   ~BlimpOutputSurface() override;
 
   // OutputSurface implementation.
   void SwapBuffers(cc::CompositorFrame* frame) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BlimpOutputSurface);
 };
 
 }  // namespace client
 }  // namespace blimp
 
 #endif  // BLIMP_CLIENT_FEATURE_COMPOSITOR_BLIMP_OUTPUT_SURFACE_H_