Disable the flaky RenderWidgetDeletedWhileMouseLockPending test

R=piman@chromium.org

Change-Id: Ie3ad9d57c1b078551a0a7e83dc84a3e95958072c
Bug: 898641
Reviewed-on: https://chromium-review.googlesource.com/c/1318385Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605460}

content/browser/web_contents/web_contents_impl_browsertest.cc

@@ -2025,8 +2025,9 @@ class MouseLockDelegate : public WebContentsDelegate {
   bool request_to_lock_mouse_called_ = false;
 };
 
+// TODO(crbug.com/898641): This test is flaky.
 IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest,
-                       RenderWidgetDeletedWhileMouseLockPending) {
+                       DISABLED_RenderWidgetDeletedWhileMouseLockPending) {
   ASSERT_TRUE(embedded_test_server()->Start());
 
   std::unique_ptr<MouseLockDelegate> delegate(new MouseLockDelegate());