Consolidate OutputSurface constructors into GL vs Vulkan.

content/renderer/gpu/mailbox_output_surface.h

Index: content/renderer/gpu/mailbox_output_surface.h
diff --git a/content/renderer/gpu/mailbox_output_surface.h b/content/renderer/gpu/mailbox_output_surface.h
index 1d4b95559f84b82270f2da3326efd300600588f8..532909595be56b81a2e8284df3145c895182914a 100644
--- a/content/renderer/gpu/mailbox_output_surface.h
+++ b/content/renderer/gpu/mailbox_output_surface.h
@@ -18,6 +18,7 @@
 
 namespace cc {
 class CompositorFrameAck;
+class ContextProvider;
 }
 
 namespace content {
@@ -32,11 +33,9 @@ class MailboxOutputSurface : public CompositorOutputSurface {
   MailboxOutputSurface(
       int32_t routing_id,
       uint32_t output_surface_id,
-      const scoped_refptr<ContextProviderCommandBuffer>& context_provider,
-      const scoped_refptr<ContextProviderCommandBuffer>&
-          worker_context_provider,
-      scoped_refptr<FrameSwapMessageQueue> swap_frame_message_queue,
-      cc::ResourceFormat format);
+      scoped_refptr<cc::ContextProvider> context_provider,
+      scoped_refptr<cc::ContextProvider> worker_context_provider,
+      scoped_refptr<FrameSwapMessageQueue> swap_frame_message_queue);
   ~MailboxOutputSurface() override;
 
   // cc::OutputSurface implementation.
@@ -72,7 +71,6 @@ class MailboxOutputSurface : public CompositorOutputSurface {
 
   uint32_t fbo_;
   bool is_backbuffer_discarded_;
-  cc::ResourceFormat format_;
 };
 
 }  // namespace content