Encrypted Media: Implement IPC based SetCdm().

content/renderer/media/android/renderer_media_player_manager.h

Index: content/renderer/media/android/renderer_media_player_manager.h
diff --git a/content/renderer/media/android/renderer_media_player_manager.h b/content/renderer/media/android/renderer_media_player_manager.h
index ed94b7639ac95db9198859a42fab34a6add6b408..bb89c3c8d6eeb2271e1a273373f94c5e01d95ba3 100644
--- a/content/renderer/media/android/renderer_media_player_manager.h
+++ b/content/renderer/media/android/renderer_media_player_manager.h
@@ -35,6 +35,8 @@ class WebMediaPlayerAndroid;
 // RenderView.
 class RendererMediaPlayerManager : public RenderViewObserver {
  public:
+  static const int kInvalidCdmId = 0;
+
   // Constructs a RendererMediaPlayerManager object for the |render_view|.
   RendererMediaPlayerManager(RenderView* render_view);
   virtual ~RendererMediaPlayerManager();
@@ -80,6 +82,10 @@ class RendererMediaPlayerManager : public RenderViewObserver {
   // Requests the player to exit fullscreen.
   void ExitFullscreen(int player_id);
 
+  // Requests the player with |player_id| to use the CDM with |cdm_id|.
+  // Does nothing if |cdm_id| is kInvalidCdmId.

[ddorwin, 2014/03/25 23:03:59]

Why? Shouldn't it detach the two? (Equivalent to setMediaKeys(0))

Do we have appropriate code for setMediaKeys(other_cdm_id) or should we assert
that this is not the case (valid ID => valid ID transition)?

Oh... because we might send this for Clear Key?

[xhwang, 2014/03/26 06:02:04]

No, we don't support setMediaKeys(0). Currently we do nothing when
setMediaKeys(0) is called (see WMPA).

With l.86, WMPA can always call manager_->SetCdm(GetCdmId()) without checking
GetCdmId(). This is consistent with
decryptor_ready_cb_.Run(web_cdm_->GetDecryptor()), where we don't check
GetDecryptor().

+  void SetCdm(int player_id, int cdm_id);
+
 #if defined(VIDEO_HOLE)
   // Requests an external surface for out-of-band compositing.
   void RequestExternalSurface(int player_id, const gfx::RectF& geometry);