platform apps: Disables history.pushState/replaceState in platform_app.js.

chrome/renderer/content_settings_observer.h

 // 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.
 
 #ifndef CHROME_RENDERER_CONTENT_SETTINGS_OBSERVER_H_
 #define CHROME_RENDERER_CONTENT_SETTINGS_OBSERVER_H_
 
 #include <map>
 #include <set>
 
@@ skipping 56 matching lines @@
   virtual bool allowIndexedDB(const blink::WebString& name,
                               const blink::WebSecurityOrigin& origin) override;
   virtual bool allowPlugins(bool enabled_per_settings) override;
   virtual bool allowScript(bool enabled_per_settings) override;
   virtual bool allowScriptFromSource(bool enabled_per_settings,
                                      const blink::WebURL& script_url) override;
   virtual bool allowStorage(bool local) override;
   virtual bool allowReadFromClipboard(bool default_value) override;
   virtual bool allowWriteToClipboard(bool default_value) override;
   virtual bool allowMutationEvents(bool default_value) override;
-  virtual bool allowPushState() override;
   virtual void didNotAllowPlugins() override;
   virtual void didNotAllowScript() override;
   virtual bool allowDisplayingInsecureContent(
       bool allowed_per_settings,
       const blink::WebSecurityOrigin& context,
       const blink::WebURL& url) override;
   virtual bool allowRunningInsecureContent(
       bool allowed_per_settings,
       const blink::WebSecurityOrigin& context,
       const blink::WebURL& url) override;
@@ skipping 75 matching lines @@
   typedef std::map<int, blink::WebPermissionCallbacks> PermissionRequestMap;
   PermissionRequestMap permission_requests_;
 
   // If true, IsWhitelistedForContentSettings will always return true.
   const bool should_whitelist_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSettingsObserver);
 };
 
 #endif  // CHROME_RENDERER_CONTENT_SETTINGS_OBSERVER_H_