Remove a chrome dependency by removing Prerender from ResourceDispatcherHost.

chrome/browser/prerender/prerender_tracker.h

 // Copyright (c) 2011 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_PRERENDER_PRERENDER_TRACKER_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_TRACKER_H_
 #pragma once
 
 #include <map>
 #include <set>
 
-#include "base/memory/singleton.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
+#include "content/browser/renderer_host/resource_dispatcher_host.h"
 
 namespace prerender {
 
 class PrerenderManager;
-struct RenderViewInfo;
 
 // PrerenderTracker is responsible for keeping track of all prerendering
 // RenderViews and their statuses.  Its list is guaranteed to be up to date
 // and can be modified on any thread.
-class PrerenderTracker {
+class PrerenderTracker : public ResourceDispatcherHost::Observer {
  public:
-  // Returns the PrerenderTracker singleton.
-  static PrerenderTracker* GetInstance();
+  PrerenderTracker();
+  virtual ~PrerenderTracker();
 
   // Attempts to set the status of the specified RenderViewHost to
   // FINAL_STATUS_USED.  Returns true on success.  Returns false if it has
   // already been cancelled for any reason, or is no longer prerendering.
   // Can only be called only on the IO thread.  This method will not call
   // PrerenderContents::set_final_status() on the corresponding
   // PrerenderContents.
   //
   // If it returns true, all subsequent calls to TryCancel for the RenderView
   // will return false.
   bool TryUse(int child_id, int route_id);
 
   // Attempts to cancel prerendering by the specified RenderView, setting the
   // FinalStatus to |final_status|.  Returns true if the specified prerender has
   // been cancelled, either as a result of this call or for any other reason.
   // If the call results in cancelling a PrerenderContents, a task to destroy
   // it is also posted to the UI thread.
   //
   // When true is returned, it is guaranteed that the RenderView will never
   // be displayed.  When false is returned, the RenderView has either been
   // swapped into a tab or has already been destroyed.
   bool TryCancel(int child_id, int route_id, FinalStatus final_status);
 
   // Same as above, but can only called on the IO Thread.  Does not acquire a
   // lock when the RenderView is not being prerendered.
   bool TryCancelOnIOThread(int child_id, int route_id,
                            FinalStatus final_status);
 
-  // Returns whether or not a RenderView is prerendering.  Can only be called on
-  // the IO thread.  Does not acquire a lock, so may claim a RenderView that has
-  // been displayed or destroyed is still prerendering.
-  // TODO(mmenke):  Remove external use of this method and make it private.
-  bool IsPrerenderingOnIOThread(int child_id, int route_id) const;
-
   // Gets the FinalStatus of the specified prerendered RenderView.  Returns
   // |true| and sets |final_status| to the status of the RenderView if it
   // is found, returns false otherwise.
   bool GetFinalStatus(int child_id, int route_id,
                       FinalStatus* final_status) const;
 
+  // ResourceDispatcherHost::Observer implementation.
+  virtual bool ShouldBeginRequest(
+      int child_id, int route_id,
+      const ResourceHostMsg_Request& request_data,
+      const content::ResourceContext& resource_context,
+      const GURL& referrer) OVERRIDE;
+
+  virtual void MutateLoadFlags(int child_id, int route_id,
+                               int* load_flags) OVERRIDE;
+
  protected:
   friend class PrerenderContents;
 
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerUsed);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerCancelled);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerCancelledOnIO);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerCancelledFast);
   FRIEND_TEST_ALL_PREFIXES(PrerenderTrackerTest, PrerenderTrackerMultiple);
 
   // Must be called when a RenderView starts prerendering, before the first
   // navigation starts to avoid any races.
   void OnPrerenderingStarted(int child_id, int route_id,
                              PrerenderManager* prerender_manager);
 
   // Must be called when a RenderView stops prerendering, either because the
   // RenderView was used or prerendering was cancelled and it is being
   // destroyed.
   void OnPrerenderingFinished(int child_id, int route_id);
 
  private:
-  friend struct DefaultSingletonTraits<PrerenderTracker>;
+  struct RenderViewInfo {
+    explicit RenderViewInfo(PrerenderManager* prerender_manager);
+    ~RenderViewInfo();
+
+    FinalStatus final_status;
+    base::WeakPtr<PrerenderManager> prerender_manager;
+  };
 
   typedef std::pair<int, int> ChildRouteIdPair;
 
   // Map of child/route id pairs to final statuses.
   typedef std::map<ChildRouteIdPair, RenderViewInfo> FinalStatusMap;
   // Set of child/route id pairs that may be prerendering.
   typedef std::set<ChildRouteIdPair> PossiblyPrerenderingChildRouteIdPairs;
 
-  PrerenderTracker();
-  ~PrerenderTracker();
-
   // Attempts to set the FinalStatus of the specified RenderView to
   // |final_status|.  If the FinalStatus of the RenderView has already been
   // set, does nothing.  Returns the resulting FinalStatus of that RenderView,
   // regardless of success or failure.  If the RenderView isn't currently
   // prerendering, returns FINAL_STATUS_MAX.
   FinalStatus SetFinalStatus(int child_id, int route_id,
                              FinalStatus final_status);
 
   // Add/remove the specified pair to |possibly_prerendering_io_thread_set_| on
   // the IO Thread.
   void AddPrerenderOnIOThread(const ChildRouteIdPair& child_route_id_pair);
   void RemovePrerenderOnIOThread(const ChildRouteIdPair& child_route_id_pair);
 
+  // Returns whether or not a RenderView is prerendering.  Can only be called on
+  // the IO thread.  Does not acquire a lock, so may claim a RenderView that has
+  // been displayed or destroyed is still prerendering.
+  bool IsPrerenderingOnIOThread(int child_id, int route_id) const;
+
   // Tasks posted to the IO Thread to call the above functions.
   static void AddPrerenderOnIOThreadTask(
       const ChildRouteIdPair& child_route_id_pair);
   static void RemovePrerenderOnIOThreadTask(
       const ChildRouteIdPair& child_route_id_pair);
 
   // |final_status_map_lock_| protects access to |final_status_map_|.
   mutable base::Lock final_status_map_lock_;
   // Map containing child/route id pairs and their final statuses.  Must only be
   // accessed while the lock is held.  Values are always accurate and up to
   // date.
   FinalStatusMap final_status_map_;
 
   // Superset of child/route id pairs that are prerendering.  Can only access on
   // the IO thread.  May contain entries that have since been displayed.  Only
   // used to prevent locking when not needed.
   PossiblyPrerenderingChildRouteIdPairs possibly_prerendering_io_thread_set_;
 
   DISALLOW_COPY_AND_ASSIGN(PrerenderTracker);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_TRACKER_H_