<webview>: Add support for filtering extension events by instanceId.

extensions/common/event_filtering_info.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 EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
 #define EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "googleurl/src/gurl.h"
 
 namespace base {
 class Value;
 }
 
 namespace extensions {
 
 // Extra information about an event that is used in event filtering.
 //
 // This is the information that is matched against criteria specified in JS
 // extension event listeners. Eg:
 //
 // chrome.someApi.onSomeEvent.addListener(cb,
 //                                        {url: [{hostSuffix: 'google.com'}],
 //                                         tabId: 1});
 class EventFilteringInfo {
  public:
   EventFilteringInfo();
   ~EventFilteringInfo();
   void SetURL(const GURL& url);
+  void SetInstanceID(int instance_id);
 
   bool has_url() const { return has_url_; }
   const GURL& url() const { return url_; }
 
-  std::string AsJSONString() const;
+  bool has_instance_id() const { return has_instance_id_; }
+  int instance_id() const { return instance_id_; }
+
   scoped_ptr<base::Value> AsValue() const;
   bool IsEmpty() const;
 
  private:
   bool has_url_;
   GURL url_;
 
+  bool has_instance_id_;
+  int instance_id_;
+
   // Allow implicit copy and assignment.
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_