Revert of Remove MediaStreamTrack.getSources().

content/renderer/media/user_media_client_impl.cc

Index: content/renderer/media/user_media_client_impl.cc
diff --git a/content/renderer/media/user_media_client_impl.cc b/content/renderer/media/user_media_client_impl.cc
index 29a9819980bc895ab2c2134a6ef8bf686e400dab..d4ea066fe24d555ee773a800d50907f67ab4b942 100644
--- a/content/renderer/media/user_media_client_impl.cc
+++ b/content/renderer/media/user_media_client_impl.cc
@@ -36,6 +36,7 @@
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
 #include "third_party/WebKit/public/platform/WebMediaDeviceInfo.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
+#include "third_party/WebKit/public/platform/WebMediaStreamTrackSourcesRequest.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 
@@ -144,6 +145,18 @@
       NOTREACHED();
       return blink::WebMediaDeviceInfo::MediaDeviceKindAudioInput;
   }
+}
+
+blink::WebSourceInfo::VideoFacingMode ToVideoFacingMode(
+    const std::string& device_label) {
+#if defined(OS_ANDROID)
+  if (device_label.find("front") != std::string::npos) {
+    return blink::WebSourceInfo::VideoFacingModeUser;
+  } else if (device_label.find("back") != std::string::npos) {
+    return blink::WebSourceInfo::VideoFacingModeEnvironment;
+  }
+#endif
+  return blink::WebSourceInfo::VideoFacingModeNone;
 }
 
 static int g_next_request_id = 0;
@@ -283,6 +296,25 @@
                  weak_factory_.GetWeakPtr(), media_devices_request));
 }
 
+void UserMediaClientImpl::requestSources(
+    const blink::WebMediaStreamTrackSourcesRequest& sources_request) {
+  // We don't call UpdateWebRTCMethodCount() here to track the API count in UMA
+  // stats. This is instead counted in MediaStreamTrack::getSources in blink.
+  DCHECK(CalledOnValidThread());
+
+  // |sources_request| can't be mocked, so in tests it will be empty (the
+  // underlying pointer is null). In order to use this function in a test we
+  // need to check if it isNull.
+  url::Origin security_origin;
+  if (!sources_request.isNull())
+    security_origin = sources_request.origin();
+
+  GetMediaDevicesDispatcher()->EnumerateDevices(
+      true /* audio input */, true /* video input */, false /* audio output */,
+      security_origin, base::Bind(&UserMediaClientImpl::FinalizeGetSources,
+                                  weak_factory_.GetWeakPtr(), sources_request));
+}
+
 void UserMediaClientImpl::setMediaDeviceChangeObserver(
     const blink::WebMediaDeviceChangeObserver& observer) {
   media_device_change_observer_ = observer;
@@ -393,6 +425,34 @@
   }
 
   EnumerateDevicesSucceded(&request, devices);
+}
+
+void UserMediaClientImpl::FinalizeGetSources(
+    blink::WebMediaStreamTrackSourcesRequest request,
+    const EnumerationResult& result) {
+  DCHECK_EQ(static_cast<size_t>(NUM_MEDIA_DEVICE_TYPES), result.size());
+
+  blink::WebVector<blink::WebSourceInfo> sources(
+      result[MEDIA_DEVICE_TYPE_AUDIO_INPUT].size() +
+      result[MEDIA_DEVICE_TYPE_VIDEO_INPUT].size());
+  size_t index = 0;
+  for (const auto& device_info : result[MEDIA_DEVICE_TYPE_AUDIO_INPUT]) {
+    sources[index++].initialize(
+        blink::WebString::fromUTF8(device_info.device_id),
+        blink::WebSourceInfo::SourceKindAudio,
+        blink::WebString::fromUTF8(device_info.label),
+        blink::WebSourceInfo::VideoFacingModeNone);
+  }
+
+  for (const auto& device_info : result[MEDIA_DEVICE_TYPE_VIDEO_INPUT]) {
+    sources[index++].initialize(
+        blink::WebString::fromUTF8(device_info.device_id),
+        blink::WebSourceInfo::SourceKindVideo,
+        blink::WebString::fromUTF8(device_info.label),
+        ToVideoFacingMode(device_info.label));
+  }
+
+  EnumerateSourcesSucceded(&request, sources);
 }
 
 // Callback from MediaStreamDispatcher.
@@ -720,6 +780,12 @@
     blink::WebMediaDevicesRequest* request,
     blink::WebVector<blink::WebMediaDeviceInfo>& devices) {
   request->requestSucceeded(devices);
+}
+
+void UserMediaClientImpl::EnumerateSourcesSucceded(
+    blink::WebMediaStreamTrackSourcesRequest* request,
+    blink::WebVector<blink::WebSourceInfo>& sources) {
+  request->requestSucceeded(sources);
 }
 
 const blink::WebMediaStreamSource* UserMediaClientImpl::FindLocalSource(