Disable WebRTC VerifyCanvasCaptureWebGLFrames (timeout-flaky).

TBR=emircan@chromium.org

Bug: 740762
Change-Id: Ib1714450f52d2fb9634c68c9bc455f09484cca39
Reviewed-on: https://chromium-review.googlesource.com/566081Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485467}

content/browser/webrtc/webrtc_capture_from_element_browsertest.cc

@@ -98,7 +98,7 @@ IN_PROC_BROWSER_TEST_F(WebRtcCaptureFromElementBrowserTest,
 }
 
 IN_PROC_BROWSER_TEST_F(WebRtcCaptureFromElementBrowserTest,
-                       VerifyCanvasCaptureWebGLFrames) {
+                       DISABLED_VerifyCanvasCaptureWebGLFrames) {
   MakeTypicalCall("testCanvasCapture(drawWebGL);", kCanvasCaptureTestHtmlFile);
 }