InstantExtended: Transient naventry for preview.

chrome/browser/instant/instant_controller.h

Index: chrome/browser/instant/instant_controller.h
diff --git a/chrome/browser/instant/instant_controller.h b/chrome/browser/instant/instant_controller.h
index 1a08425b39423b7f64eba611099f18fa94b632fc..c9cae091480cc0269cbd6319f19ab5a5d8677671 100644
--- a/chrome/browser/instant/instant_controller.h
+++ b/chrome/browser/instant/instant_controller.h
@@ -40,6 +40,7 @@ class BrowserInstantController;
 }
 
 namespace content {
+class NavigationEntry;
 class WebContents;
 }
 
@@ -264,6 +265,19 @@ class InstantController : public InstantPage::Delegate {
                    int height,
                    InstantSizeUnits units);
 
+  // Copies the loader's active NavigationEntry into a transient history entry
+  // for the active tab. Used to update the tab title and make the back button
+  // work as expected when the preview is shown at full height but not yet
+  // committed.
+  void SetTransientHistoryEntry();
+
+  // Updates the URL in the transient history entry for the overlay.
+  void UpdateTransientHistoryEntry(const GURL& url);
+
+  // Discards any transient history entry set by Instant.
+  // See SetTransientHistoryEntry().
+  void ResetTransientHistoryEntry();
+
   // Send the omnibox popup bounds to the page.
   void SendPopupBoundsToPage();
 
@@ -391,6 +405,9 @@ class InstantController : public InstantPage::Delegate {
   // List of events and their timestamps, useful in debugging Instant behaviour.
   mutable std::list<std::pair<int64, std::string> > debug_events_;
 
+  // True iff Instant has set a transient history entry for the active tab.
+  bool instant_set_transient_entry_;
+
   DISALLOW_COPY_AND_ASSIGN(InstantController);
 };