Add back RenderFrameHost sanity-check to AudioRendererHost.

content/browser/renderer_host/media/audio_renderer_host.h

Index: content/browser/renderer_host/media/audio_renderer_host.h
diff --git a/content/browser/renderer_host/media/audio_renderer_host.h b/content/browser/renderer_host/media/audio_renderer_host.h
index 7252086657dc01d89cff53846874d7cf4201b9f0..8640111ea93bc6d606aa918c7b048782e59031c7 100644
--- a/content/browser/renderer_host/media/audio_renderer_host.h
+++ b/content/browser/renderer_host/media/audio_renderer_host.h
@@ -129,6 +129,14 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
                               const AudioOutputDeviceInfo& device_info)>
       OutputDeviceInfoCB;
 
+  // Function that is run on the UI thread to check whether the routing IDs
+  // reference a valid RenderFrameHost. The function then runs |callback| on the
+  // IO thread with true/false if valid/invalid.
+  using ValidateRenderFrameIdFunction =
+      void (*)(int render_process_id,
+               int render_frame_id,
+               const base::Callback<void(bool)>& callback);
+
   ~AudioRendererHost() override;
 
   // Methods called on IO thread ----------------------------------------------
@@ -186,7 +194,8 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   void DoCreateStream(int stream_id,
                       int render_frame_id,
                       const media::AudioParameters& params,
-                      const std::string& device_unique_id);
+                      const std::string& device_unique_id,
+                      bool render_frame_is_valid);
 
   // Complete the process of creating an audio stream. This will set up the
   // shared memory or shared socket in low latency mode and send the
@@ -237,6 +246,13 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   // |stream_id| has started.
   bool IsAuthorizationStarted(int stream_id);
 
+  // Called from AudioRendererHostTest to override the function that checks for
+  // the existence of the render frame at stream creation time.
+  void set_render_frame_id_validate_function_for_testing(
+      ValidateRenderFrameIdFunction function) {
+    validate_render_frame_id_function_ = function;
+  }
+
   // ID of the RenderProcessHost that owns this instance.
   const int render_process_id_;
 
@@ -267,6 +283,10 @@ class CONTENT_EXPORT AudioRendererHost : public BrowserMessageFilter {
   // host. Reported as UMA stat at shutdown.
   size_t max_simultaneous_streams_;
 
+  // Function to use to validate render frame IDs. This is only overridden for
+  // testing.
+  ValidateRenderFrameIdFunction validate_render_frame_id_function_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioRendererHost);
 };