Handle interface to prerenders.

chrome/browser/predictors/autocomplete_action_predictor.cc

 // 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.
 
 #include "chrome/browser/predictors/autocomplete_action_predictor.h"
 
 #include <math.h>
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/guid.h"
 #include "base/i18n/case_conversion.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_log.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/autocomplete_result.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/history/in_memory_database.h"
 #include "chrome/browser/predictors/autocomplete_action_predictor_factory.h"
 #include "chrome/browser/predictors/predictor_database.h"
 #include "chrome/browser/predictors/predictor_database_factory.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
+#include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 
 namespace {
@@ skipping 107 matching lines @@
                   i->destination_url) == match_it->urls.end()) {
       match_it->urls.push_back(i->destination_url);
     }
   }
 }
 
 void AutocompleteActionPredictor::ClearTransitionalMatches() {
   transitional_matches_.clear();
 }
 
+void AutocompleteActionPredictor::StartPrerendering(
+    const GURL& url,
+    content::SessionStorageNamespace* session_storage_namespace,
+    const gfx::Size& size) {
+  prerender_handle_.reset();

[dominich, 2012/07/12 16:16:48]

I'm not a fan of the double reset. Would something like:

PrerenderHandle* handle = NULL;
if (... GetForProfile(...)) {
  handle = prerender_manager->AddPrerenderFromOmnibox(...);
}
prerender_handle_.reset(handle);

satisfy mmenke and gavinp?

[mmenke, 2012/07/12 16:26:51]

This affects the final status.  Resetting the old prerender handle results in a
cancellation, while swapping will result in an eviction.

[gavinp, 2012/07/13 12:02:22]

Added a comment explaining why the reset first is important.

On 2012/07/12 16:26:51, Matt Menke wrote:

+  if (prerender::PrerenderManager* prerender_manager =
+          prerender::PrerenderManagerFactory::GetForProfile(profile_)) {
+    prerender_handle_.reset(
+        prerender_manager->AddPrerenderFromOmnibox(
+            url, session_storage_namespace, size));
+  }
+}
+
 // Given a match, return a recommended action.
 AutocompleteActionPredictor::Action
     AutocompleteActionPredictor::RecommendAction(
         const string16& user_text,
         const AutocompleteMatch& match) const {
   bool is_in_db = false;
   const double confidence = CalculateConfidence(user_text, match, &is_in_db);
   DCHECK(confidence >= 0.0 && confidence <= 1.0);
 
   UMA_HISTOGRAM_BOOLEAN("AutocompleteActionPredictor.MatchIsInDb", is_in_db);
@@ skipping 384 matching lines @@
   return number_of_hits / (number_of_hits + value.number_of_misses);
 }
 
 AutocompleteActionPredictor::TransitionalMatch::TransitionalMatch() {
 }
 
 AutocompleteActionPredictor::TransitionalMatch::~TransitionalMatch() {
 }
 
 }  // namespace predictors