Chromecast: add platform hooks to inject browser/renderer message filters.

chromecast/renderer/cast_render_process_observer.h

Index: chromecast/renderer/cast_render_process_observer.h
diff --git a/chromecast/renderer/cast_render_process_observer.h b/chromecast/renderer/cast_render_process_observer.h
index ca992bc9bc6117c64efd59e331bf9624177480ba..0c28b58174b687400f0c32f03a76c40767f4162b 100644
--- a/chromecast/renderer/cast_render_process_observer.h
+++ b/chromecast/renderer/cast_render_process_observer.h
@@ -5,10 +5,16 @@
 #ifndef CHROMECAST_RENDERER_CAST_RENDER_PROCESS_OBSERVER_H_
 #define CHROMECAST_RENDERER_CAST_RENDER_PROCESS_OBSERVER_H_
 
+#include <vector>
+
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/public/renderer/render_process_observer.h"
 
+namespace IPC {
+class MessageFilter;
+}
+
 namespace chromecast {
 namespace media {
 class CmaMessageFilterProxy;
@@ -18,7 +24,9 @@ namespace shell {
 
 class CastRenderProcessObserver : public content::RenderProcessObserver {
  public:
-  CastRenderProcessObserver();
+  CastRenderProcessObserver(
+      const std::vector<scoped_refptr<IPC::MessageFilter>>&
+          platform_message_filters);
   ~CastRenderProcessObserver() override;
 
  private:
@@ -30,6 +38,7 @@ class CastRenderProcessObserver : public content::RenderProcessObserver {
 #if !defined(OS_ANDROID)
   scoped_refptr<media::CmaMessageFilterProxy> cma_message_filter_proxy_;
 #endif  // !defined(OS_ANDROID)
+  std::vector<scoped_refptr<IPC::MessageFilter>> platform_message_filters_;
 
   DISALLOW_COPY_AND_ASSIGN(CastRenderProcessObserver);
 };