content: Cleanup class/struct forward declarations

content/public/test/mock_render_process_host.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_TEST_MOCK_RENDER_PROCESS_HOST_H_
 #define CONTENT_PUBLIC_TEST_MOCK_RENDER_PROCESS_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <memory>
 #include <utility>
 
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/metrics/persistent_memory_allocator.h"
 #include "base/observer_list.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_process_host_factory.h"
 #include "ipc/ipc_test_sink.h"
 #include "mojo/public/cpp/bindings/associated_interface_ptr.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
 
 class StoragePartition;
 
 namespace content {
 
 class MockRenderProcessHostFactory;
+class RenderWidgetHost;
 
 // A mock render process host that has no corresponding renderer process.  All
 // IPC messages are sent into the message sink for inspection by tests.
 class MockRenderProcessHost : public RenderProcessHost {
  public:
   explicit MockRenderProcessHost(BrowserContext* browser_context);
   ~MockRenderProcessHost() override;
 
   // Provides access to all IPC messages that would have been sent to the
   // renderer via this RenderProcessHost.
@@ skipping 151 matching lines @@
   // for deleting all MockRenderProcessHosts that have not deleted by a test in
   // the destructor and prevent them from being leaked.
   mutable ScopedVector<MockRenderProcessHost> processes_;
 
   DISALLOW_COPY_AND_ASSIGN(MockRenderProcessHostFactory);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_MOCK_RENDER_PROCESS_HOST_H_