Revert of "win: Set is_clang=true by default" over the weekend.

chrome/browser/prerender/prerender_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <deque>
 #include <set>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ skipping 1991 matching lines @@
 
 // Checks that scripts can retrieve the correct window size while prerendering.
 IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderWindowSize) {
   PrerenderTestURL("/prerender/prerender_size.html", FINAL_STATUS_USED, 1);
   NavigateToDestURL();
 }
 
 // TODO(jam): http://crbug.com/350550
 #if !(defined(OS_CHROMEOS) && defined(ADDRESS_SANITIZER))
 
-// TODO(hans): Temporarily disable while enabling Clang by default on Windows
-// over the weekend. (crbug.com/727458)
-#if !(defined(OS_WIN) && defined(__clang__))
-
 // Checks that prerenderers will terminate when the RenderView crashes.
 IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderRendererCrash) {
   std::unique_ptr<TestPrerender> prerender = PrerenderTestURL(
       "/prerender/prerender_page.html", FINAL_STATUS_RENDERER_CRASHED, 1);
 
   // Navigate to about:crash and then wait for the renderer to crash.
   ASSERT_TRUE(prerender->contents());
   ASSERT_TRUE(prerender->contents()->prerender_contents());
   prerender->contents()->prerender_contents()->GetController().
       LoadURL(
           GURL(content::kChromeUICrashURL),
           content::Referrer(),
           ui::PAGE_TRANSITION_TYPED,
           std::string());
   prerender->WaitForStop();
 }
 #endif
-#endif
 
 IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest,
                        PrerenderPageWithFragment) {
   PrerenderTestURL("/prerender/prerender_page.html#fragment", FINAL_STATUS_USED,
                    1);
 
   ChannelDestructionWatcher channel_close_watcher;
   channel_close_watcher.WatchChannel(browser()->tab_strip_model()->
       GetActiveWebContents()->GetRenderProcessHost());
   NavigateToDestURL();
@@ skipping 1889 matching lines @@
   ASSERT_TRUE(content::ExecuteScriptAndExtractBool(web_contents,
                                                    "DidDisplayReallyPass()",
                                                    &display_test_result));
   ASSERT_TRUE(display_test_result);
 }
 #endif  // !defined(DISABLE_NACL)
 
 }  // namespace prerender
 
 #endif  // !defined(OS_MACOSX) || !defined(ADDRESS_SANITIZER)