[PPAPI][MediaStream] Support configure for video input.

content/renderer/pepper/pepper_media_stream_track_host_base.h

 // 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.
 
 #ifndef CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_TRACK_HOST_BASE_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_TRACK_HOST_BASE_H_
 
 #include "base/compiler_specific.h"
 #include "content/common/content_export.h"
 #include "ppapi/host/resource_host.h"
@@ skipping 15 matching lines @@
   bool InitBuffers(int32_t number_of_buffers, int32_t buffer_size);
 
   ppapi::MediaStreamBufferManager* buffer_manager() { return &buffer_manager_; }
 
   // Sends a buffer index to the corresponding MediaStreamTrackResourceBase
   // via an IPC message. The resource adds the buffer index into its
   // |buffer_manager_| for reading or writing.
   // Also see |MediaStreamBufferManager|.
   void SendEnqueueBufferMessageToPlugin(int32_t index);
 
- private:
-  // Subclasses must implement this method to clean up when the track is closed.
-  virtual void OnClose() = 0;
-
   // ResourceMessageHandler overrides:
   virtual int32_t OnResourceMessageReceived(
       const IPC::Message& msg,
       ppapi::host::HostMessageContext* context) OVERRIDE;
 
+ private:
+  // Subclasses must implement this method to clean up when the track is closed.
+  virtual void OnClose() = 0;
+
   // Message handlers:
   int32_t OnHostMsgEnqueueBuffer(ppapi::host::HostMessageContext* context,

[yzshen1, 2014/02/14 18:25:44]

By the way, I just realized that this method doesn't validate |index|. Moreover,
MediaStreamBuffer only do DCHECKs. In a release build, a malicious IPC message
can easily get us into out-of-bound array access.

[Peng, 2014/02/14 20:04:50]

I changed several DCHECK to CHECK in MediaStreamBufferManager(). It will crash
any compromised renderer or plugin.  

                                 int32_t index);
   int32_t OnHostMsgClose(ppapi::host::HostMessageContext* context);
 
   RendererPpapiHost* host_;
 
   ppapi::MediaStreamBufferManager buffer_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperMediaStreamTrackHostBase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_TRACK_HOST_BASE_H_