Make WebRtcWebcamBrowserTest fail faster.

chrome/browser/media/chrome_webrtc_webcam_browsertest.cc

Index: chrome/browser/media/chrome_webrtc_webcam_browsertest.cc
diff --git a/chrome/browser/media/chrome_webrtc_webcam_browsertest.cc b/chrome/browser/media/chrome_webrtc_webcam_browsertest.cc
index 5f4a3eaa0e66ebf3df5d83ae3bf8be04735ef8c9..1daff0305230e5d35c93aa5cd54f5512820ac8c5 100644
--- a/chrome/browser/media/chrome_webrtc_webcam_browsertest.cc
+++ b/chrome/browser/media/chrome_webrtc_webcam_browsertest.cc
@@ -55,12 +55,13 @@ class WebRtcWebcamBrowserTest : public WebRtcTestBase,
 
   std::string GetUserMediaAndGetStreamSize(content::WebContents* tab,
                                            const std::string& constraints) {
-    GetUserMediaWithSpecificConstraintsAndAccept(tab, constraints);
-
-    StartDetectingVideo(tab, "local-view");
-    WaitForVideoToPlay(tab);
-    std::string actual_stream_size = GetStreamSize(tab, "local-view");
-    CloseLastLocalStream(tab);
+    std::string actual_stream_size;
+    if (GetUserMediaWithSpecificConstraintsAndAccept(tab, constraints)) {
+      StartDetectingVideo(tab, "local-view");
+      if (WaitForVideoToPlay(tab))
+        actual_stream_size = GetStreamSize(tab, "local-view");
+      CloseLastLocalStream(tab);
+    }
     return actual_stream_size;
   }