Add a new app API to enable watchdog behavior restarts in kiosk apps

extensions/browser/test_extensions_browser_client.h

Index: extensions/browser/test_extensions_browser_client.h
diff --git a/extensions/browser/test_extensions_browser_client.h b/extensions/browser/test_extensions_browser_client.h
index e66fe98910ef7c1c5ff974fd74bf1c503132fba2..fd4495ba8c8a9ecece43202717fe6921ea69b1f7 100644
--- a/extensions/browser/test_extensions_browser_client.h
+++ b/extensions/browser/test_extensions_browser_client.h
@@ -14,6 +14,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "build/build_config.h"
+#include "components/pref_registry/testing_pref_service_syncable.h"
 #include "components/update_client/update_client.h"
 #include "extensions/browser/extensions_browser_client.h"
 #include "extensions/browser/updater/extension_cache.h"
@@ -114,6 +115,10 @@ class TestExtensionsBrowserClient : public ExtensionsBrowserClient {
   scoped_refptr<update_client::UpdateClient> CreateUpdateClient(
       content::BrowserContext* context) override;
 
+  user_prefs::TestingPrefServiceSyncable* testing_pref_service() {
+    return &testing_pref_service_;
+  }
+
  private:
   content::BrowserContext* main_context_;       // Not owned.
   content::BrowserContext* incognito_context_;  // Not owned, defaults to NULL.
@@ -128,6 +133,8 @@ class TestExtensionsBrowserClient : public ExtensionsBrowserClient {
 
   base::Callback<update_client::UpdateClient*(void)> update_client_factory_;
 
+  user_prefs::TestingPrefServiceSyncable testing_pref_service_;
+
   DISALLOW_COPY_AND_ASSIGN(TestExtensionsBrowserClient);
 };