Add support for response header manipulation in Declarative WebRequest API

chrome/browser/extensions/api/declarative_webrequest/webrequest_rule.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_BROWSER_EXTENSIONS_API_DECLARATIVE_WEBREQUEST_WEBREQUEST_RULE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_WEBREQUEST_WEBREQUEST_RULE_H_
 #pragma once
 
 #include <list>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/time.h"
 #include "chrome/browser/extensions/api/declarative/rules_registry.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/request_stages.h"
 
 namespace extensions {
 class URLMatcherConditionFactory;
 class WebRequestConditionSet;
 class WebRequestActionSet;
 }
 
 namespace extension_web_request_api_helpers {
 struct EventResponseDelta;
 }
 
 namespace net {
+class HttpResponseHeaders;
 class URLRequest;
 }
 
 namespace extensions {
 
 typedef linked_ptr<extension_web_request_api_helpers::EventResponseDelta>
     LinkedPtrEventResponseDelta;
 
 // Representation of a rule of the declarative Web Request API
 class WebRequestRule {
  public:
   typedef std::string ExtensionId;
   typedef std::string RuleId;
   typedef std::pair<ExtensionId, RuleId> GlobalRuleId;
   typedef int Priority;
 
+  // Container to pass additional information about requests that are not
+  // available in all request stages.
+  struct OptionalRequestData {
+    OptionalRequestData() : original_response_headers(0) {}

[Matt Perry, 2012/05/29 21:24:27]

use NULL rather than 0

[battre, 2012/05/30 07:35:06]

Done.

+    net::HttpResponseHeaders* original_response_headers;
+  };
+
   WebRequestRule(const GlobalRuleId& id,
                  base::Time extension_installation_time,
                  scoped_ptr<WebRequestConditionSet> conditions,
                  scoped_ptr<WebRequestActionSet> actions,
                  Priority priority);
   virtual ~WebRequestRule();
 
   // If |error| is empty, the translation was successful and the returned
   // rule is internally consistent.
   static scoped_ptr<WebRequestRule> Create(
       URLMatcherConditionFactory* url_matcher_condition_factory,
       const std::string& extension_id,
       base::Time extension_installation_time,
       linked_ptr<RulesRegistry::Rule> rule,
       std::string* error);
 
   const GlobalRuleId& id() const { return id_; }
   const WebRequestConditionSet& conditions() const { return *conditions_; }
   const WebRequestActionSet& actions() const { return *actions_; }
   Priority priority() const { return priority_; }
 
   std::list<LinkedPtrEventResponseDelta> CreateDeltas(
       net::URLRequest* request,
-      RequestStages request_stage) const;
+      RequestStages request_stage,
+      const OptionalRequestData& optional_request_data) const;
 
   // Returns the minimum priority of rules that may be evaluated after
   // this rule. Defaults to MAX_INT. Only valid if the conditions of this rule
   // are fulfilled.
   Priority GetMinimumPriority() const;
 
  private:
   // Checks whether the set of |conditions| and |actions| are consistent,
   // meaning for example that we do not allow combining an |action| that needs
   // to be executed before the |condition| can be fulfilled.
   // Returns true in case of consistency and MUST set |error| otherwise.
   static bool CheckConsistency(WebRequestConditionSet* conditions,
                                WebRequestActionSet* actions,
                                std::string* error);
 
   GlobalRuleId id_;
   base::Time extension_installation_time_;  // For precedences of rules.
   scoped_ptr<WebRequestConditionSet> conditions_;
   scoped_ptr<WebRequestActionSet> actions_;
   Priority priority_;
 
   DISALLOW_COPY_AND_ASSIGN(WebRequestRule);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_WEBREQUEST_WEBREQUEST_RULE_H_