Reenable WebrtcBrowserTest.CanMakeEmptyCallThenAddStreamsAndRenegotiateEnable test again.

The underalying problem is now fixed. See http://crbug/293125 and  https://code.google.com/p/webrtc/source/detail?r=5870

BUG=293125, 362431

Review URL: https://codereview.chromium.org/254713004

Cr-Commit-Position: refs/heads/master@{#291648}

content/browser/media/webrtc_browsertest.cc

@@ -154,11 +154,8 @@ IN_PROC_BROWSER_TEST_F(WebRtcBrowserTest, MANUAL_CanSetupCallAndSendDtmf) {
   MakeTypicalPeerConnectionCall("callAndSendDtmf(\'123,abc\');");
 }
 
-// TODO(phoglund): this test fails because the peer connection state will be
-// stable in the second negotiation round rather than have-local-offer.
-// http://crbug.com/293125.
 IN_PROC_BROWSER_TEST_F(WebRtcBrowserTest,
-                       DISABLED_CanMakeEmptyCallThenAddStreamsAndRenegotiate) {
+                       CanMakeEmptyCallThenAddStreamsAndRenegotiate) {
   const char* kJavascript =
       "callEmptyThenAddOneStreamAndRenegotiate({video: true, audio: true});";
   MakeTypicalPeerConnectionCall(kJavascript);