Bind BrowserCdmManager callbacks to UI thread before passing to CDM.

content/browser/media/cdm/browser_cdm_manager.cc

Index: content/browser/media/cdm/browser_cdm_manager.cc
diff --git a/content/browser/media/cdm/browser_cdm_manager.cc b/content/browser/media/cdm/browser_cdm_manager.cc
index 3eb55f1efc9e383c9f5620ed46b56770a1994a89..5dbbd7d5e107ec4f7bad417b3268b6f2886fb020 100644
--- a/content/browser/media/cdm/browser_cdm_manager.cc
+++ b/content/browser/media/cdm/browser_cdm_manager.cc
@@ -20,6 +20,7 @@
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
+#include "media/base/bind_to_current_loop.h"
 #include "media/base/browser_cdm.h"
 #include "media/base/browser_cdm_factory.h"
 #include "media/base/cdm_promise.h"
@@ -439,9 +440,10 @@ void BrowserCdmManager::OnDestroyCdm(int render_frame_id, int cdm_id) {
 }
 
 // Use a weak pointer here instead of |this| to avoid circular references.
-#define BROWSER_CDM_MANAGER_CB(func)                                   \
-  base::Bind(&BrowserCdmManager::func, weak_ptr_factory_.GetWeakPtr(), \
-             render_frame_id, cdm_id)
+#define BROWSER_CDM_MANAGER_CB(func)                                       \
+  media::BindToCurrentLoop(                                                \
+      base::Bind(&BrowserCdmManager::func, weak_ptr_factory_.GetWeakPtr(), \
+                 render_frame_id, cdm_id))

[xhwang, 2015/04/20 18:21:12]

This will cause those callbacks to be posted always, even on Android where
everything lives on the UI thread. This is okay since the binded callbacks
aren't very frequent. Can you add a comment on why this is needed and note that
this will always cause a post?

 
 void BrowserCdmManager::AddCdm(int render_frame_id,
                                int cdm_id,