Handle interface to prerenders.

chrome/browser/predictors/autocomplete_action_predictor.h

Index: chrome/browser/predictors/autocomplete_action_predictor.h
diff --git a/chrome/browser/predictors/autocomplete_action_predictor.h b/chrome/browser/predictors/autocomplete_action_predictor.h
index afbba8354ca71bd138c8fd5d4b3a71a8e2c5abe4..d1ac1082baddcb7fe0fa49e1f8216892f9945b85 100644
--- a/chrome/browser/predictors/autocomplete_action_predictor.h
+++ b/chrome/browser/predictors/autocomplete_action_predictor.h
@@ -10,6 +10,7 @@
 
 #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"
@@ -18,6 +19,7 @@
 #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;
@@ -26,10 +28,18 @@ 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
@@ -79,6 +89,15 @@ class AutocompleteActionPredictor
   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);
@@ -199,6 +218,8 @@ class AutocompleteActionPredictor
   // 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_;