Handle interface to prerenders.

chrome/browser/prerender/prerender_contents.h

Index: chrome/browser/prerender/prerender_contents.h
diff --git a/chrome/browser/prerender/prerender_contents.h b/chrome/browser/prerender/prerender_contents.h
index 6156d486d3a56ddbfb413bd965ae7132b4aa9e69..62ed4e7e42cbd5b4d25c3913be6b7b976bff40c2 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -15,6 +15,7 @@
 #include "base/time.h"
 #include "base/values.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
+#include "chrome/browser/prerender/prerender_handle.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
@@ -66,10 +67,6 @@ class PrerenderContents : public content::NotificationObserver,
     DISALLOW_COPY_AND_ASSIGN(Factory);
   };
 
-  // Information on pages that the prerendered page has tried to prerender.
-  struct PendingPrerenderInfo;
-  typedef std::list<PendingPrerenderInfo> PendingPrerenderList;
-
   // Indicates how this PrerenderContents relates to MatchComplete. This is to
   // figure out which histograms to use to record the FinalStatus, Match (record
   // all prerenders and control group prerenders) or MatchComplete (record
@@ -80,7 +77,7 @@ class PrerenderContents : public content::NotificationObserver,
     // MatchComplete.
     MATCH_COMPLETE_DEFAULT,
     // A prerender that used to be a regular prerender, but has since been
-    // replaced by a MatchComplete dummy.  Therefore, we will record this only
+    // replaced by a MatchComplete dummy. Therefore, we will record this only
     // for Match, but not for MatchComplete.
     MATCH_COMPLETE_REPLACED,
     // A prerender that is a MatchComplete dummy replacing a regular prerender.
@@ -95,6 +92,12 @@ class PrerenderContents : public content::NotificationObserver,
 
   virtual ~PrerenderContents();
 
+  // For MatchComplete correctness, create a dummy replacement prerender
+  // contents to stand in for this prerender contents that (which we are about
+  // to destroy).
+  void MakeIntoDummyReplacementOf(

[dominich, 2012/06/28 00:34:32]

can this be a separate CL?

+      const PrerenderContents* original_prerender_contents);
+
   bool Init();
 
   static Factory* CreateFactory();
@@ -153,6 +156,10 @@ class PrerenderContents : public content::NotificationObserver,
   Origin origin() const { return origin_; }
   uint8 experiment_id() const { return experiment_id_; }
 
+  int client_count() const { return client_count_; }

[dominich, 2012/06/28 00:34:32]

usage count? instance count?

+  void IncrementClientCount();
+  void DecrementClientCount();
+
   base::TimeTicks load_start_time() const { return load_start_time_; }
 
   // Indicates whether this prerendered page can be used for the provided
@@ -160,7 +167,9 @@ class PrerenderContents : public content::NotificationObserver,
   // set to the URL that is found as a match if it is provided.
   // TODO(gavinp,mmenke): Rework matching to be based on both the URL
   // and the session WebStorage.
-  bool MatchesURL(const GURL& url, GURL* matching_url) const;
+  bool Matches(

[dominich, 2012/06/28 00:34:32]

we didn't use the returned matching_url anywhere? if not, then change the
comment please.

+      const GURL& url,
+      const content::SessionStorageNamespace* session_storage_namespace);
 
   // content::WebContentsObserver implementation.
   virtual void DidStopLoading() OVERRIDE;
@@ -212,19 +221,33 @@ class PrerenderContents : public content::NotificationObserver,
   // MouseEvent being dispatched by a link to a website installed as an app.
   bool IsCrossSiteNavigationPending() const;
 
-  // Adds a pending prerender to the list.
-  virtual void AddPendingPrerender(const GURL& url,
-                                   const content::Referrer& referrer,
-                                   const gfx::Size& size);
+  virtual PrerenderHandle AddPendingPrerender(const GURL& url,
+                                              const content::Referrer& referrer,
+                                              const gfx::Size& size);
 
   // Returns true if |url| corresponds to a pending prerender.

[dominich, 2012/06/28 00:34:32]

comment

-  bool IsPendingEntry(const GURL& url) const;
+  bool IsPendingEntry(PrerenderHandle prerender_handle) const;
 
   // Reissues any pending prerender requests from the prerendered page.  Also
   // clears the list of pending requests.
   void StartPendingPrerenders();
 
  protected:
+  // Information on pages that the prerendered page has tried to prerender.
+  struct PendingPrerenderInfo {

[dominich, 2012/06/28 00:34:32]

I believe this can just be a forward reference here, and then actually defined
in the .cc file as before.

If not, why not?

+    PendingPrerenderInfo(PrerenderHandleImpl* prerender_handle_impl,
+                         const GURL& url,
+                         const content::Referrer& referrer,
+                         const gfx::Size& size);
+
+    PrerenderHandleImpl* prerender_handle_impl;

[dominich, 2012/06/28 00:34:32]

const PrerenderHandleImpl?

+    const GURL url;
+    const content::Referrer referrer;
+    const gfx::Size size;
+  };
+  typedef std::list<PendingPrerenderInfo> PendingPrerenderList;
+

[dominich, 2012/06/28 00:34:32]

nit: extra blank line

+
   PrerenderContents(PrerenderManager* prerender_manager,
                     PrerenderTracker* prerender_tracker,
                     Profile* profile,
@@ -255,6 +278,11 @@ class PrerenderContents : public content::NotificationObserver,
 
   bool prerendering_has_started_;
 
+  // Time at which we started to load the URL.  This is used to compute
+  // the time elapsed from initiating a prerender until the time the
+  // (potentially only partially) prerendered page is shown to the user.
+  base::TimeTicks load_start_time_;
+
  private:
   class TabContentsDelegateImpl;
 
@@ -303,6 +331,15 @@ class PrerenderContents : public content::NotificationObserver,
   // such as HTTP redirects or javascript redirects.
   std::vector<GURL> alias_urls_;
 
+  // The session storage namespace for use in Matching. We must save it
+  // rather than get it from the RenderViewHost since in the control group
+  // we won't have a RenderViewHost.
+  content::SessionStorageNamespace* session_storage_namespace_;
+
+  // Number of distinct clients of this prerendered page (distinct link elements

[dominich, 2012/06/28 00:34:32]

instances?

+  // for instance).
+  int client_count_;
+
   bool has_stopped_loading_;
 
   // True when the main frame has finished loading.
@@ -321,11 +358,6 @@ class PrerenderContents : public content::NotificationObserver,
   // Used solely to prevent double deletion.
   bool prerendering_has_been_cancelled_;
 
-  // Time at which we started to load the URL.  This is used to compute
-  // the time elapsed from initiating a prerender until the time the
-  // (potentially only partially) prerendered page is shown to the user.
-  base::TimeTicks load_start_time_;
-
   // Process Metrics of the render process associated with the
   // RenderViewHost for this object.
   scoped_ptr<base::ProcessMetrics> process_metrics_;