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

chromecast/renderer/cast_render_process_observer.cc

 // Copyright 2014 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.
 
 #include "chromecast/renderer/cast_render_process_observer.h"
 
 #include "chromecast/renderer/media/cma_message_filter_proxy.h"
 #include "content/public/renderer/render_thread.h"
 
 namespace chromecast {
 namespace shell {
 
-CastRenderProcessObserver::CastRenderProcessObserver() {
+CastRenderProcessObserver::CastRenderProcessObserver(
+    const std::vector<scoped_refptr<IPC::MessageFilter>>&
+        platform_message_filters)
+    : platform_message_filters_(platform_message_filters) {
   content::RenderThread* thread = content::RenderThread::Get();
   thread->AddObserver(this);
   CreateCustomFilters();
 }
 
 CastRenderProcessObserver::~CastRenderProcessObserver() {
   // CastRenderProcessObserver outlives content::RenderThread.
   // No need to explicitly call RemoveObserver in teardown.
 }
 
 void CastRenderProcessObserver::CreateCustomFilters() {
+  content::RenderThread* thread = content::RenderThread::Get();
 #if !defined(OS_ANDROID)
-  content::RenderThread* thread = content::RenderThread::Get();
   cma_message_filter_proxy_ =
       new media::CmaMessageFilterProxy(thread->GetIOMessageLoopProxy());
   thread->AddFilter(cma_message_filter_proxy_.get());
 #endif  // !defined(OS_ANDROID)
+  for (const auto& filter : platform_message_filters_) {
+    thread->AddFilter(filter.get());
+  }
 }
 
 void CastRenderProcessObserver::OnRenderProcessShutdown() {
+  content::RenderThread* thread = content::RenderThread::Get();
 #if !defined(OS_ANDROID)
-  content::RenderThread* thread = content::RenderThread::Get();
   if (cma_message_filter_proxy_.get()) {
     thread->RemoveFilter(cma_message_filter_proxy_.get());
     cma_message_filter_proxy_ = NULL;
   }
 #endif  // !defined(OS_ANDROID)
+  for (auto& filter : platform_message_filters_) {
+    if (filter.get()) {
+      thread->RemoveFilter(filter.get());
+      filter = nullptr;
+    }
+  }
+  platform_message_filters_.clear();
 }
 
 }  // namespace shell
 }  // namespace chromecast