Add histogram WebRTC.UserMediaRequest.NoResultState to track user media requests with no result.

content/renderer/media/media_stream_impl.h

 // Copyright (c) 2012 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_MEDIA_MEDIA_STREAM_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 128 matching lines @@
         const blink::WebMediaStreamSource& source,
         const blink::WebMediaConstraints& constraints);
 
     // Triggers |callback| when all sources used in this request have either
     // successfully started, or a source has failed to start.
     void CallbackOnTracksStarted(const ResourcesReady& callback);
 
     bool IsSourceUsed(const blink::WebMediaStreamSource& source) const;
     void RemoveSource(const blink::WebMediaStreamSource& source);
 
-    bool AreAllSourcesRemoved() const { return sources_.empty(); }
+    bool HasPendingSources() const;
 
    private:
     void OnTrackStarted(MediaStreamSource* source, bool success);
     void CheckAllTracksStarted();
 
     ResourcesReady ready_callback_;
     bool request_failed_;
     // Sources used in this request.
     std::vector<blink::WebMediaStreamSource> sources_;
     std::vector<MediaStreamSource*> sources_waiting_for_callback_;
@@ skipping 24 matching lines @@
       const blink::WebMediaConstraints& constraints,
       blink::WebVector<blink::WebMediaStreamTrack>* webkit_tracks,
       UserMediaRequestInfo* request);
 
   // Callback function triggered when all native versions of the
   // underlying media sources and tracks have been created and started.
   void OnCreateNativeTracksCompleted(
       UserMediaRequestInfo* request,
       content::MediaStreamRequestResult result);
 
+  void OnStreamGeneratedForCancelledRequest(

[vrk (LEFT CHROMIUM), 2014/08/06 17:28:36]

nit: Can you comment on what these arguments are?

[andresp-chromium, 2014/08/06 18:00:22]

Nope. They are also not documented for OnStreamGenerated and I am not the best
to document that :|

I also considered naming this method describing what it does, but couldn't find
such a name and so named it describing when it gets called.

+      const StreamDeviceInfoArray& audio_array,
+      const StreamDeviceInfoArray& video_array);
+
   UserMediaRequestInfo* FindUserMediaRequestInfo(int request_id);
   UserMediaRequestInfo* FindUserMediaRequestInfo(
       const blink::WebUserMediaRequest& request);
   void DeleteUserMediaRequestInfo(UserMediaRequestInfo* request);
+  void DeleteAllUserMediaRequests();
 
   MediaDevicesRequestInfo* FindMediaDevicesRequestInfo(int request_id);
   MediaDevicesRequestInfo* FindMediaDevicesRequestInfo(
       const blink::WebMediaDevicesRequest& request);
   void CancelAndDeleteMediaDevicesRequest(MediaDevicesRequestInfo* request);
 
   // Returns the source that use a device with |device.session_id|
   // and |device.device.id|. NULL if such source doesn't exist.
   const blink::WebMediaStreamSource* FindLocalSource(
       const StreamDeviceInfo& device) const;
@@ skipping 21 matching lines @@
   // Note: This member must be the last to ensure all outstanding weak pointers
   // are invalidated first.
   base::WeakPtrFactory<MediaStreamImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_IMPL_H_