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

BUG=399835

Review URL: https://codereview.chromium.org/446553002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287862 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/media/media_stream_impl.cc

@@ -199,6 +199,7 @@ void MediaStreamImpl::cancelUserMediaRequest(
     // We can't abort the stream generation process.
     // Instead, erase the request. Once the stream is generated we will stop the
     // stream if the request does not exist.
+    LogUserMediaRequestWithNoResult(MEDIA_STREAM_REQUEST_EXPLICITLY_CANCELLED);
     DeleteUserMediaRequestInfo(request);
   }
 }
@@ -275,20 +276,8 @@ void MediaStreamImpl::OnStreamGenerated(
   if (!request_info) {
     // This can happen if the request is canceled or the frame reloads while
     // MediaStreamDispatcher is processing the request.
-    // Only stop the device if the device is not used in another MediaStream.
-    for (StreamDeviceInfoArray::const_iterator device_it = audio_array.begin();
-         device_it != audio_array.end(); ++device_it) {
-      if (!FindLocalSource(*device_it))
-        media_stream_dispatcher_->StopStreamDevice(*device_it);
-    }
-
-    for (StreamDeviceInfoArray::const_iterator device_it = video_array.begin();
-         device_it != video_array.end(); ++device_it) {
-      if (!FindLocalSource(*device_it))
-        media_stream_dispatcher_->StopStreamDevice(*device_it);
-    }
-
     DVLOG(1) << "Request ID not found";
+    OnStreamGeneratedForCancelledRequest(audio_array, video_array);
     return;
   }
   request_info->generated = true;
@@ -332,6 +321,23 @@ void MediaStreamImpl::OnStreamGenerated(
                  weak_factory_.GetWeakPtr()));
 }
 
+void MediaStreamImpl::OnStreamGeneratedForCancelledRequest(
+    const StreamDeviceInfoArray& audio_array,
+    const StreamDeviceInfoArray& video_array) {
+  // Only stop the device if the device is not used in another MediaStream.
+  for (StreamDeviceInfoArray::const_iterator device_it = audio_array.begin();
+       device_it != audio_array.end(); ++device_it) {
+    if (!FindLocalSource(*device_it))
+      media_stream_dispatcher_->StopStreamDevice(*device_it);
+  }
+
+  for (StreamDeviceInfoArray::const_iterator device_it = video_array.begin();
+       device_it != video_array.end(); ++device_it) {
+    if (!FindLocalSource(*device_it))
+      media_stream_dispatcher_->StopStreamDevice(*device_it);
+  }
+}
+
 // Callback from MediaStreamDispatcher.
 // The requested stream failed to be generated.
 void MediaStreamImpl::OnStreamGenerationFailed(
@@ -701,6 +707,29 @@ void MediaStreamImpl::DeleteUserMediaRequestInfo(
   NOTREACHED();
 }
 
+void MediaStreamImpl::DeleteAllUserMediaRequests() {
+  UserMediaRequests::iterator request_it = user_media_requests_.begin();
+  while (request_it != user_media_requests_.end()) {
+    DVLOG(1) << "MediaStreamImpl@" << this << "::DeleteAllUserMediaRequests: "
+             << "Cancel user media request " << (*request_it)->request_id;
+    // If the request is not generated, it means that a request
+    // has been sent to the MediaStreamDispatcher to generate a stream
+    // but MediaStreamDispatcher has not yet responded and we need to cancel
+    // the request.
+    if (!(*request_it)->generated) {
+      DCHECK(!(*request_it)->HasPendingSources());
+      media_stream_dispatcher_->CancelGenerateStream(
+          (*request_it)->request_id, weak_factory_.GetWeakPtr());
+      LogUserMediaRequestWithNoResult(MEDIA_STREAM_REQUEST_NOT_GENERATED);
+    } else {
+      DCHECK((*request_it)->HasPendingSources());
+      LogUserMediaRequestWithNoResult(
+          MEDIA_STREAM_REQUEST_PENDING_MEDIA_TRACKS);
+    }
+    request_it = user_media_requests_.erase(request_it);
+  }
+}
+
 MediaStreamImpl::MediaDevicesRequestInfo*
 MediaStreamImpl::FindMediaDevicesRequestInfo(
     int request_id) {
@@ -748,20 +777,7 @@ void MediaStreamImpl::CancelAndDeleteMediaDevicesRequest(
 
 void MediaStreamImpl::FrameWillClose() {
   // Cancel all outstanding UserMediaRequests.
-  UserMediaRequests::iterator request_it = user_media_requests_.begin();
-  while (request_it != user_media_requests_.end()) {
-    DVLOG(1) << "MediaStreamImpl@" << this << "::FrameWillClose: "
-             << "Cancel user media request " << (*request_it)->request_id;
-    // If the request is not generated, it means that a request
-    // has been sent to the MediaStreamDispatcher to generate a stream
-    // but MediaStreamDispatcher has not yet responded and we need to cancel
-    // the request.
-    if (!(*request_it)->generated) {
-      media_stream_dispatcher_->CancelGenerateStream(
-          (*request_it)->request_id, weak_factory_.GetWeakPtr());
-    }
-    request_it = user_media_requests_.erase(request_it);
-  }
+  DeleteAllUserMediaRequests();
 
   // Loop through all current local sources and stop the sources.
   LocalStreamSources::iterator sources_it = local_sources_.begin();
@@ -910,4 +926,8 @@ void MediaStreamImpl::UserMediaRequestInfo::RemoveSource(
   }
 }
 
+bool MediaStreamImpl::UserMediaRequestInfo::HasPendingSources() const {
+  return !sources_waiting_for_callback_.empty();
+}
+
 }  // namespace content

content/renderer/media/media_stream_impl.h

@@ -146,7 +146,7 @@ class CONTENT_EXPORT MediaStreamImpl
     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);
@@ -191,10 +191,15 @@ class CONTENT_EXPORT MediaStreamImpl
       UserMediaRequestInfo* request,
       content::MediaStreamRequestResult result);
 
+  void OnStreamGeneratedForCancelledRequest(
+      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(

content/renderer/media/webrtc_uma_histograms.cc

@@ -8,6 +8,12 @@
 
 namespace content {
 
+void LogUserMediaRequestWithNoResult(MediaStreamRequestState state) {
+  UMA_HISTOGRAM_ENUMERATION("WebRTC.UserMediaRequest.NoResultState",
+                            state,
+                            NUM_MEDIA_STREAM_REQUEST_WITH_NO_RESULT);
+}
+
 void LogUserMediaRequestResult(MediaStreamRequestResult result) {
   UMA_HISTOGRAM_ENUMERATION(
       "WebRTC.UserMediaRequest.Result", result, NUM_MEDIA_REQUEST_RESULTS);

content/renderer/media/webrtc_uma_histograms.h

@@ -12,6 +12,21 @@
 
 namespace content {
 
+// Used to investigate where UserMediaRequests end up.
+// Only UserMediaRequests that do not log with LogUserMediaRequestResult
+// should call LogUserMediaRequestWithNoResult.
+//
+// Elements in this enum should not be deleted or rearranged; the only
+// permitted operation is to add new elements before
+// NUM_MEDIA_STREAM_REQUEST_WITH_NO_RESULT.
+enum MediaStreamRequestState {
+  MEDIA_STREAM_REQUEST_EXPLICITLY_CANCELLED = 0,
+  MEDIA_STREAM_REQUEST_NOT_GENERATED = 1,
+  MEDIA_STREAM_REQUEST_PENDING_MEDIA_TRACKS = 2,
+  NUM_MEDIA_STREAM_REQUEST_WITH_NO_RESULT
+};
+
+void LogUserMediaRequestWithNoResult(MediaStreamRequestState state);
 void LogUserMediaRequestResult(MediaStreamRequestResult result);
 
 // Helper enum used for histogramming calls to WebRTC APIs from JavaScript.

tools/metrics/histograms/histograms.xml

@@ -35798,6 +35798,20 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="WebRTC.UserMediaRequest.NoResultState"
+    enum="MediaStreamRequestState">
+  <owner>andresp@chromium.org</owner>
+  <summary>
+    The state of a UserMediaRequest when it gets destroyed before having a
+    result.
+
+    Note: &quot;Explicitly Cancelled&quot; means
+    MediaStreamImpl::cancelUserMediaRequest was called and not necessarily that
+    the user cancelled. Those are likely tracked as UserMediaRequest with a
+    result of permission denied.
+  </summary>
+</histogram>
+
 <histogram name="WebRTC.UserMediaRequest.Result"
     enum="MediaStreamRequestResult">
   <owner>andresp@chromium.org</owner>
@@ -43332,6 +43346,12 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="8" label="Track Start Failure"/>
 </enum>
 
+<enum name="MediaStreamRequestState" type="int">
+  <int value="0" label="Explicitly Cancelled"/>
+  <int value="1" label="Stream Not Generated"/>
+  <int value="2" label="Pending Media Tracks"/>
+</enum>
+
 <enum name="MetaTagTypeEnum" type="int">
   <int value="0" label="No viewport tag"/>
   <int value="1" label="Viewport meta with device width"/>