Bug 210635

As of r260230 (GTK Release X11 build 13366), some API tests are flaky failing due to the WebProcess crashing in an unexpected way.

Tests:

* /webkit/WebKitWebView/install-missing-plugins-permission-request - Failure already tracked in bug147822
* /webkit/WebKitWebView/is-playing-audio

Could not get a stack trace yet.

stderr:

ERROR:../../Tools/TestWebKitAPI/glib/WebKitGLib/WebViewTest.cpp:74:static gboolean WebViewTest::webProcessTerminated(WebKitWebView*, WebKitWebProcessTerminationReason, WebViewTest*): code should not be reached
failed to create drawable

(WebKitWebProcess:129808): Gdk-ERROR **: 12:00:44.269: The program 'WebKitWebProcess' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadMatch (invalid parameter attributes)'.
  (Details: serial 224 error_code 8 request_code 148 (GLX) minor_code 34)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the GDK_SYNCHRONIZE environment
   variable to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)


Given both tests try to load a <video> tag, maybe related to bug198830?