Fix ExtensionServiceTest.ClearExtensionData flakiness

chrome/browser/extensions/extension_service_unittest.cc

Index: chrome/browser/extensions/extension_service_unittest.cc
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index 3b749066bfb741c5364d497814ee36b03abc4ea8..0b166431fc6508a8cbc0ce9f7c966f396e44c4cf 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -25,6 +25,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/thread_test_helper.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ -4262,13 +4263,7 @@ class ExtensionCookieCallback {
 };
 
 // Verifies extension state is removed upon uninstall.
-#if defined(OS_CHROMEOS)
-// http://crbug.com/396504
-#define MAYBE_ClearExtensionData DISABLED_ClearExtensionData
-#else
-#define MAYBE_ClearExtensionData ClearExtensionData
-#endif
-TEST_F(ExtensionServiceTest, MAYBE_ClearExtensionData) {
+TEST_F(ExtensionServiceTest, ClearExtensionData) {
   InitializeEmptyExtensionService();
   ExtensionCookieCallback callback;
 
@@ -4340,6 +4335,12 @@ TEST_F(ExtensionServiceTest, MAYBE_ClearExtensionData) {
   // Uninstall the extension.
   service()->UninstallExtension(
       good_crx, extensions::UNINSTALL_REASON_FOR_TESTING, NULL);
+  // The data deletion happens on the IO thread.
+  scoped_refptr<base::ThreadTestHelper> wait_for_io_thread(

[awong, 2014/07/28 15:05:25]

unrelated: Why is ThreadTestHelper refcounted? :-/

+      new base::ThreadTestHelper(
+          content::BrowserThread::GetMessageLoopProxyForThread(
+              content::BrowserThread::IO)));
+  EXPECT_TRUE(wait_for_io_thread->Run());
   base::RunLoop().RunUntilIdle();
 
   // Check that the cookie is gone.