Revert of Temporarily disable a failing test. (patchset #1 id:1 of...

Revert of Temporarily disable a failing test. (patchset #1 id:1 of https://codereview.chromium.org/1039103002/)

Reason for revert:
The reason for failure have been fixed in https://codereview.chromium.org/1036143003/.

Original issue's description:
> Temporarily disable a failing test.
>
> TBR=tommi
> BUG=471132
>
> Committed: https://crrev.com/17b636d978f6f6924d6323cf7414ad67f41f3d92
> Cr-Commit-Position: refs/heads/master@{#322529}

TBR=tommi@chromium.org,pkasting@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=471132

Review URL: https://codereview.chromium.org/1039053004

Cr-Commit-Position: refs/heads/master@{#322563}

chrome/browser/media/chrome_webrtc_browsertest.cc

@@ -44,10 +44,8 @@ class WebRtcBrowserTest : public WebRtcTestBase {
 #define MAYBE_RunsAudioVideoWebRTCCallInTwoTabs \
     DISABLED_RunsAudioVideoWebRTCCallInTwoTabs
 #else
-// TODO(pkasting): http://crbug.com/471132 Temporarily disabled this test due to
-// unexplained failure.
 #define MAYBE_RunsAudioVideoWebRTCCallInTwoTabs \
-    DISABLED_RunsAudioVideoWebRTCCallInTwoTabs
+    RunsAudioVideoWebRTCCallInTwoTabs
 #endif
 
 IN_PROC_BROWSER_TEST_F(WebRtcBrowserTest,