<webview> Implement clear http cache API.

extensions/browser/guest_view/web_view/web_view_guest_delegate.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_GUEST_VIEW_WEB_VIEW_WEB_VIEW_GUEST_DELEGATE_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_WEB_VIEW_WEB_VIEW_GUEST_DELEGATE_H_
 
+#include "base/callback.h"
 #include "extensions/browser/guest_view/guest_view_base.h"
 
 namespace content {
 class RenderViewHost;
 class WebContents;
 }  // namespace content
 
 namespace extensions {
 
 class WebViewGuest;
 
 namespace api {
 namespace web_view_internal {
 
 struct ContextMenuItem;
 }  // namespace web_view_internal
 }  // namespace api
 
 // A delegate class of WebViewGuest that are not a part of chrome.
 class WebViewGuestDelegate {
  public :
   virtual ~WebViewGuestDelegate() {}
 
   typedef std::vector<linked_ptr<api::web_view_internal::ContextMenuItem> >
       MenuItemVector;
 
+  // Clears http cache for this guest's StoragePartition.
+  virtual void ClearCache(base::Time remove_since,
+                          const base::Closure& callback) = 0;
+
   // Called when context menu operation was handled.
   virtual bool HandleContextMenu(const content::ContextMenuParams& params) = 0;
 
   // Called to attach helpers just after additional initialization is performed.
   virtual void OnAttachWebViewHelpers(content::WebContents* contents) = 0;
 
   // Called when the guest WebContents commits a provisional load in any frame.
   virtual void OnDidCommitProvisionalLoadForFrame(bool is_main_frame) = 0;
 
   // Called just after additional initialization is performed.
@@ skipping 10 matching lines @@
   // menu items to contain only the items from |items|.
   // |items| == NULL means no filtering will be applied.
   virtual void OnShowContextMenu(
       int request_id,
       const MenuItemVector* items) = 0;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_WEB_VIEW_WEB_VIEW_GUEST_DELEGATE_H_