Handle interface to prerenders.

chrome/browser/predictors/autocomplete_action_predictor.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_PREDICTORS_AUTOCOMPLETE_ACTION_PREDICTOR_H_
 #define CHROME_BROWSER_PREDICTORS_AUTOCOMPLETE_ACTION_PREDICTOR_H_
 #pragma once
 
 #include <map>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/string16.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/predictors/autocomplete_action_predictor_table.h"
 #include "chrome/browser/profiles/profile_keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "googleurl/src/gurl.h"
+#include "ui/gfx/size.h"
 
 struct AutocompleteLog;
 struct AutocompleteMatch;
 class AutocompleteResult;
 class HistoryService;
 class PredictorsHandler;
 class Profile;
 
+namespace content {
+  class SessionStorageNamespace;

[mmenke, 2012/07/09 18:06:57]

nit:  Don't indent.

[gavinp, 2012/07/11 17:04:00]

Done.

+}
+
 namespace history {
 class URLDatabase;
 }
 
+namespace prerender {
+class PrerenderHandle;
+}
+
 namespace predictors {
 
 // This class is responsible for determining the correct predictive network
 // action to take given for a given AutocompleteMatch and entered text. It can
 // be instantiated for both normal and incognito profiles.  For normal profiles,
 // it uses an AutocompleteActionPredictorTable accessed asynchronously on the DB
 // thread to permanently store the data used to make predictions, and keeps
 // local caches of that data to be able to make predictions synchronously on the
 // UI thread where it lives.  For incognito profiles, there is no table; the
 // local caches are copied from the main profile at creation and from there on
@@ skipping 29 matching lines @@
 
   // Return the recommended action given |user_text|, the text the user has
   // entered in the Omnibox, and |match|, the suggestion from Autocomplete.
   // This method uses information from the ShortcutsBackend including how much
   // of the matching entry the user typed, and how long it's been since the user
   // visited the matching URL, to calculate a score between 0 and 1. This score
   // is then mapped to an Action.
   Action RecommendAction(const string16& user_text,
                          const AutocompleteMatch& match) const;
 
+  // Begin prerendering |url| with |session_storage_namespace|. The |size| gives
+  // the initial size for the target prerender. The predictor will run at most
+  // one prerender at a time, so launching a prerender will cancel our previous
+  // prerenders (if any).
+  void StartPrerendering(
+      const GURL& url,
+      content::SessionStorageNamespace* session_storage_namespace,
+      gfx::Size size);

[mmenke, 2012/07/09 18:06:57]

Hmm...  size is passed by reference to prerender_link manager, but by value here
(and in PrerenderManager).  I'd recommend being consistent, unless there's a
reason we need it by value here.  Know by value's needed in one of the
PrerenderManager cases.

[dominich, 2012/07/09 18:25:43]

IIRC, it was done like this to show that it might change/be set by the method.
I'd also prefer by value everywhere for consistency, but then users of the API
don't actually need to know if it's being copied or referenced so maybe it
doesn't matter.

[gavinp, 2012/07/11 17:04:00]

Done, I went with by reference everywhere.

+
   // Return true if the suggestion type warrants a TCP/IP preconnection.
   // i.e., it is now quite likely that the user will select the related domain.
   static bool IsPreconnectable(const AutocompleteMatch& match);
 
  private:
   friend class AutocompleteActionPredictorTest;
   friend class ::PredictorsHandler;
 
   struct TransitionalMatch {
     TransitionalMatch();
@@ skipping 100 matching lines @@
   AutocompleteActionPredictor* incognito_predictor_;
 
   // The backing data store.  This is NULL for incognito-owned predictors.
   scoped_refptr<AutocompleteActionPredictorTable> table_;
 
   content::NotificationRegistrar notification_registrar_;
 
   // This is cleared after every Omnibox navigation.
   std::vector<TransitionalMatch> transitional_matches_;
 
+  scoped_ptr<prerender::PrerenderHandle> prerender_handle_;
+
   // This allows us to predict the effect of confidence threshold changes on
   // accuracy.  This is cleared after every omnibox navigation.
   mutable std::vector<std::pair<GURL, double> > tracked_urls_;
 
   // Local caches of the data store.  For incognito-owned predictors this is the
   // only copy of the data.
   DBCacheMap db_cache_;
   DBIdCacheMap db_id_cache_;
 
   bool initialized_;
 
   DISALLOW_COPY_AND_ASSIGN(AutocompleteActionPredictor);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_AUTOCOMPLETE_ACTION_PREDICTOR_H_