Revert "Disable flaky test WebRtcMediaRecorderTest.IllegalStartWhilePausedThrowsDOMError on TSAN"

This reverts commit 1e35e703.

Reason for revert: The underlying problem should now be solved.

Original change's description:
> Disable flaky test WebRtcMediaRecorderTest.IllegalStartWhilePausedThrowsDOMError on TSAN
> 
> TBR=imcheng@chromium.org
> NOTRY=true
> 
> Bug: 736268
> Change-Id: I6abc58c3ad3fff9b03929e6d4cf45aff6573ce39
> Reviewed-on: https://chromium-review.googlesource.com/548915
> Reviewed-by: Xida Chen <xidachen@chromium.org>
> Commit-Queue: Xida Chen <xidachen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#482290}

TBR=imcheng@chromium.org,xidachen@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 736268
Change-Id: I23910a3333d44e32167f16c797d9499d43e157cb
Reviewed-on: https://chromium-review.googlesource.com/563317Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Oskar Sundbom <ossu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#484933}

content/browser/webrtc/webrtc_media_recorder_browsertest.cc

@@ -175,16 +175,8 @@ IN_PROC_BROWSER_TEST_F(WebRtcMediaRecorderTest,
                   kMediaRecorderHtmlFile);
 }
 
-// Flaky on Linux Tsan (crbug.com/736268)
-#if defined(THREAD_SANITIZER)
-#define MAYBE_IllegalStartWhilePausedThrowsDOMError \
-  DISABLED_IllegalStartWhilePausedThrowsDOMError
-#else
-#define MAYBE_IllegalStartWhilePausedThrowsDOMError \
-  IllegalStartWhilePausedThrowsDOMError
-#endif
 IN_PROC_BROWSER_TEST_F(WebRtcMediaRecorderTest,
-                       MAYBE_IllegalStartWhilePausedThrowsDOMError) {
+                       IllegalStartWhilePausedThrowsDOMError) {
   MakeTypicalCall("testIllegalStartInPausedStateThrowsDOMError();",
                   kMediaRecorderHtmlFile);
 }