Faster Reload: Specify AllowCaching = false for some URLDataSources that need it

chrome/browser/search/iframe_source.h

 // 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.
 
 #ifndef CHROME_BROWSER_SEARCH_IFRAME_SOURCE_H_
 #define CHROME_BROWSER_SEARCH_IFRAME_SOURCE_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/public/browser/url_data_source.h"
 
 // Base class for URL data sources for chrome-search:// iframed content.
 class IframeSource : public content::URLDataSource {
  public:
   IframeSource();
   ~IframeSource() override;
 
  protected:
   // Overridden from content::URLDataSource:
   std::string GetMimeType(const std::string& path_and_query) const override;
+  bool AllowCaching() const override;
   bool ShouldDenyXFrameOptions() const override;
   bool ShouldServiceRequest(const net::URLRequest* request) const override;
 
   // Returns whether this source should serve data for a particular path.
   virtual bool ServesPath(const std::string& path) const = 0;
 
   // Sends unmodified resource bytes.
   void SendResource(
       int resource_id,
       const content::URLDataSource::GotDataCallback& callback);
 
   // Sends Javascript with an expected postMessage origin interpolated.
   void SendJSWithOrigin(
       int resource_id,
       const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
       const content::URLDataSource::GotDataCallback& callback);
 
   // This is exposed for testing and should not be overridden.
   // Sets |origin| to the URL of the WebContents identified by |wc_getter|.
   // Returns true if successful and false if not, for example if the WebContents
   // does not exist
   virtual bool GetOrigin(
       const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
       std::string* origin) const;
 
   DISALLOW_COPY_AND_ASSIGN(IframeSource);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_IFRAME_SOURCE_H_