Disable AppCacheNetworkServiceBrowserTest.AppCacheRequestsAreProxied

This test is flaky, see bug for details.

Bug: 1080708
Change-Id: Iea61c27cc41b1945345d495b98542fe583c4e588
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210495
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Auto-Submit: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770659}

content/browser/appcache/appcache_browsertest.cc

@@ -273,8 +273,9 @@ class LoaderFactoryInterceptingBrowserClient : public TestContentBrowserClient {
   std::vector<std::unique_ptr<PassThroughURLLoaderFactory>> proxies_;
 };
 
+// Timeout waiting for "AppCache updated" title (http://crbug.com/1080708).
 IN_PROC_BROWSER_TEST_F(AppCacheNetworkServiceBrowserTest,
-                       AppCacheRequestsAreProxied) {
+                       DISABLED_AppCacheRequestsAreProxied) {
   LoaderFactoryInterceptingBrowserClient browser_client;
   ContentBrowserClient* original_client =
       SetBrowserClientForTesting(&browser_client);