BrowserCdmManager: gets RenderFrameHost instance on the correct thread.

content/browser/media/cdm/browser_cdm_manager.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 "content/browser/media/cdm/browser_cdm_manager.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/task_runner.h"
@@ skipping 207 matching lines @@
     case CREATE_SESSION_TYPE_MP4:
       mime_type = "video/mp4";
       break;
     default:
       NOTREACHED();
       return;
   }
 
 #if defined(OS_ANDROID)
   if (CommandLine::ForCurrentProcess()
       ->HasSwitch(switches::kDisableInfobarForProtectedMediaIdentifier)) {

[gunsch, 2014/11/17 16:57:33]

somewhat related: is there any particular reason this flag is guarded with
OS_ANDROID? Since we enable this for Chromecast across the board, it would save
us the hop to the UI thread that will end up just calling
CreateSessionIfPermitted(..., true) anyways if we could enable that flag.

[xhwang, 2014/11/17 23:38:17]

I guess it's because this flag is only defined on Android:
https://code.google.com/p/chromium/codesearch#chromium/src/media/base/media_s...

If you find this useful on other platforms, feel free to fix it.

     CreateSessionIfPermitted(
         render_frame_id, cdm_id, session_id, mime_type, init_data, true);
     return;
   }
 #endif
 
   BrowserCdm* cdm = GetCdm(render_frame_id, cdm_id);
   if (!cdm) {
     DLOG(WARNING) << "No CDM found for: " << render_frame_id << ", " << cdm_id;
     SendSessionError(render_frame_id, cdm_id, session_id);
     return;
   }
 
   std::map<uint64, GURL>::const_iterator iter =
       cdm_security_origin_map_.find(GetId(render_frame_id, cdm_id));
   if (iter == cdm_security_origin_map_.end()) {
     NOTREACHED();
     SendSessionError(render_frame_id, cdm_id, session_id);
     return;
   }
   GURL security_origin = iter->second;
 
-  RenderFrameHost* rfh =
-      RenderFrameHost::FromID(render_process_id_, render_frame_id);
-  WebContents* web_contents = WebContents::FromRenderFrameHost(rfh);
-  DCHECK(web_contents);
-  GetContentClient()->browser()->RequestPermission(
-      content::PERMISSION_PROTECTED_MEDIA,
-      web_contents,
-      0,  // bridge id
-      security_origin,
-      // Only implemented for Android infobars which do not support
-      // user gestures.
-      true,
-      base::Bind(&BrowserCdmManager::CreateSessionIfPermitted,
-                 this,
-                 render_frame_id,
-                 cdm_id,
-                 session_id,
-                 mime_type,
-                 init_data));
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    BrowserThread::PostTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&BrowserCdmManager::RequestSessionPermission,
+                   this,
+                   render_frame_id,
+                   security_origin,
+                   cdm_id,
+                   session_id,
+                   mime_type,
+                   init_data));
+    return;
+  }
+  RequestSessionPermission(render_frame_id,
+                           security_origin,
+                           cdm_id,
+                           session_id,
+                           mime_type,
+                           init_data);

[xhwang, 2014/11/17 23:38:17]

Can you do the thread check and post within RequestSessionPermission()? This
function is already too long...

[gunsch, 2014/11/19 21:59:01]

Done.

 }
 
 void BrowserCdmManager::OnUpdateSession(
     int render_frame_id,
     int cdm_id,
     uint32 session_id,
     const std::vector<uint8>& response) {
   BrowserCdm* cdm = GetCdm(render_frame_id, cdm_id);
   if (!cdm) {
     DLOG(WARNING) << "No CDM found for: " << render_frame_id << ", " << cdm_id;
@@ skipping 69 matching lines @@
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   cdm_map_.erase(id);
   cdm_security_origin_map_.erase(id);
   if (cdm_cancel_permission_map_.count(id)) {
     cdm_cancel_permission_map_[id].Run();
     cdm_cancel_permission_map_.erase(id);
   }
 }
 
+void BrowserCdmManager::RequestSessionPermission(
+    int render_frame_id,
+    const GURL& security_origin,
+    int cdm_id,
+    uint32 session_id,
+    const std::string& content_type,
+    const std::vector<uint8>& init_data) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);

[xhwang, 2014/11/17 23:38:17]

See comment above. Check thread and post RequestSessionPermission() if we are
not on the right thread.

[gunsch, 2014/11/19 21:59:01]

Done.

+  RenderFrameHost* rfh =
+      RenderFrameHost::FromID(render_process_id_, render_frame_id);
+  WebContents* web_contents = WebContents::FromRenderFrameHost(rfh);
+  DCHECK(web_contents);
+  GetContentClient()->browser()->RequestPermission(
+      content::PERMISSION_PROTECTED_MEDIA,
+      web_contents,
+      0,  // bridge id
+      security_origin,
+      // Only implemented for Android infobars which do not support
+      // user gestures.
+      true,
+      base::Bind(&BrowserCdmManager::CreateSessionIfPermitted,
+                 this,
+                 render_frame_id,
+                 cdm_id,
+                 session_id,
+                 content_type,
+                 init_data));
+}
+
 void BrowserCdmManager::CreateSessionIfPermitted(
     int render_frame_id,
     int cdm_id,
     uint32 session_id,
     const std::string& content_type,
     const std::vector<uint8>& init_data,
     bool permitted) {
   cdm_cancel_permission_map_.erase(GetId(render_frame_id, cdm_id));
   if (!permitted) {
     SendSessionError(render_frame_id, cdm_id, session_id);
     return;
   }
 
   BrowserCdm* cdm = GetCdm(render_frame_id, cdm_id);
   if (!cdm) {
     DLOG(WARNING) << "No CDM found for: " << render_frame_id << ", " << cdm_id;
     SendSessionError(render_frame_id, cdm_id, session_id);
     return;
   }
 
   // This could fail, in which case a SessionError will be fired.
   cdm->CreateSession(session_id, content_type, &init_data[0], init_data.size());
 }
 
 }  // namespace content