Break dependency of native_viewport_service on mojo::shell::Context

mojo/services/native_viewport/native_viewport.h

Index: mojo/services/native_viewport/native_viewport.h
diff --git a/mojo/services/native_viewport/native_viewport.h b/mojo/services/native_viewport/native_viewport.h
index d33f33ff889f30c198ffec659a7d3f17b3e7682b..f1c764e49c14a576886ef3c50313ae4e24607c63 100644
--- a/mojo/services/native_viewport/native_viewport.h
+++ b/mojo/services/native_viewport/native_viewport.h
@@ -19,12 +19,10 @@ class Event;
 }
 
 namespace mojo {
-namespace shell {
-class Context;
-}
-
 namespace services {
 
+class NativeViewportContext;
+
 class NativeViewportDelegate {
  public:
   virtual ~NativeViewportDelegate() {}
@@ -53,7 +51,7 @@ class NativeViewport {
   virtual void ReleaseCapture() = 0;
 
   // |context| is NULL when loaded into separate process.
-  static scoped_ptr<NativeViewport> Create(shell::Context* context,
+  static scoped_ptr<NativeViewport> Create(NativeViewportContext* context,
                                            NativeViewportDelegate* delegate);
 };