Fixed the problem at the source of the flaky WebViewTest.ShimArcAttribute test.

chrome/browser/apps/web_view_browsertest.cc

 // Copyright 2013 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 "base/path_service.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/apps/app_browsertest_util.h"
 #include "chrome/browser/chrome_content_browser_client.h"
 #include "chrome/browser/prerender/prerender_link_manager.h"
@@ skipping 1236 matching lines @@
   content::WebContents* guest_web_contents =
       GetGuestViewManager()->WaitForSingleGuestCreated();
   ASSERT_TRUE(guest_web_contents->GetRenderProcessHost()->IsIsolatedGuest());
   content::WaitForInterstitialAttach(guest_web_contents);
 
   // Now close the app while interstitial page being shown in guest.
   extensions::AppWindow* window = GetFirstAppWindow();
   window->GetBaseWindow()->Close();
 }
 
-#if defined(OS_LINUX)
-// http://crbug.com/431604
-#define MAYBE_ShimSrcAttribute DISABLED_ShimSrcAttribute
-#else
-#define MAYBE_ShimSrcAttribute ShimSrcAttribute
-#endif
-IN_PROC_BROWSER_TEST_F(WebViewTest, MAYBE_ShimSrcAttribute) {
+IN_PROC_BROWSER_TEST_F(WebViewTest, ShimSrcAttribute) {
   ASSERT_TRUE(RunPlatformAppTest("platform_apps/web_view/src_attribute"))
       << message_;
 }
 
 // This test verifies that prerendering has been disabled inside <webview>.
 // This test is here rather than in PrerenderBrowserTest for testing convenience
 // only. If it breaks then this is a bug in the prerenderer.
 IN_PROC_BROWSER_TEST_F(WebViewTest, NoPrerenderer) {
   ASSERT_TRUE(StartEmbeddedTestServer());
   content::WebContents* guest_web_contents =
@@ skipping 1033 matching lines @@
 // http://crbug.com/403325
 #define MAYBE_WebViewInBackgroundPage \
     DISABLED_WebViewInBackgroundPage
 #else
 #define MAYBE_WebViewInBackgroundPage WebViewInBackgroundPage
 #endif
 IN_PROC_BROWSER_TEST_F(WebViewTest, MAYBE_WebViewInBackgroundPage) {
   ASSERT_TRUE(RunExtensionTest("platform_apps/web_view/background"))
       << message_;
 }