predictors: Key the resource prefetcher by URL, not navigation.

chrome/browser/predictors/resource_prefetcher.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 CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCHER_H_
 #define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCHER_H_
 
 #include <stddef.h>
 
 #include <list>
 #include <map>
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/threading/thread_checker.h"
 #include "chrome/browser/predictors/resource_prefetch_common.h"
 #include "net/url_request/redirect_info.h"
 #include "net/url_request/url_request.h"
 #include "url/gurl.h"
 
 namespace net {
 class URLRequestContext;
 }
 
 namespace predictors {
 
-// Responsible for prefetching resources for a single navigation based on the
-// input list of resources.
+// Responsible for prefetching resources for a single main frame URL based on
+// the input list of resources.
 //  - Limits the max number of resources in flight for any host and also across
 //    hosts.
 //  - When stopped, will wait for the pending requests to finish.
 //  - Lives entirely on the IO thread.
 class ResourcePrefetcher : public net::URLRequest::Delegate {
  public:
   // Used to communicate when the prefetching is done. All methods are invoked
   // on the IO thread.
   class Delegate {
    public:
     virtual ~Delegate() { }
 
     // Called when the ResourcePrefetcher is finished, i.e. there is nothing
     // pending in flight.
     virtual void ResourcePrefetcherFinished(ResourcePrefetcher* prefetcher) = 0;
 
     virtual net::URLRequestContext* GetURLRequestContext() = 0;
   };
 
   // |delegate| has to outlive the ResourcePrefetcher.
   ResourcePrefetcher(Delegate* delegate,
                      const ResourcePrefetchPredictorConfig& config,
-                     const NavigationID& navigation_id,
-                     PrefetchKeyType key_type,
+                     const GURL& main_frame_url,
                      const std::vector<GURL>& urls);
   ~ResourcePrefetcher() override;
 
   void Start();  // Kicks off the prefetching. Can only be called once.
   void Stop();   // No additional prefetches will be queued after this.
 
-  const NavigationID& navigation_id() const { return navigation_id_; }
-  PrefetchKeyType key_type() const { return key_type_; }
+  const GURL& main_frame_url() const { return main_frame_url_; }
 
  private:
   friend class ResourcePrefetcherTest;
   friend class TestResourcePrefetcher;
 
   // Launches new prefetch requests if possible.
   void TryToLaunchPrefetchRequests();
 
   // Starts a net::URLRequest for the input |url|.
   void SendRequest(const GURL& url);
@@ skipping 32 matching lines @@
     INITIALIZED = 0,  // Prefetching hasn't started.
     RUNNING = 1,      // Prefetching started, allowed to add more requests.
     STOPPED = 2,      // Prefetching started, not allowed to add more requests.
     FINISHED = 3      // No more inflight request, new requests not possible.
   };
 
   base::ThreadChecker thread_checker_;
   PrefetcherState state_;
   Delegate* const delegate_;
   ResourcePrefetchPredictorConfig const config_;
-  NavigationID navigation_id_;
-  PrefetchKeyType key_type_;
+  GURL main_frame_url_;
   std::unique_ptr<GURL> urls_;
 
   std::map<net::URLRequest*, std::unique_ptr<net::URLRequest>>
       inflight_requests_;
   std::list<GURL> request_queue_;
   std::map<std::string, size_t> host_inflight_counts_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourcePrefetcher);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCHER_H_