InstantExtended: Transient naventry for preview.

chrome/browser/instant/instant_controller.cc

Index: chrome/browser/instant/instant_controller.cc
diff --git a/chrome/browser/instant/instant_controller.cc b/chrome/browser/instant/instant_controller.cc
index 80f9b796a4cf181a57ac371c9af2bab3abe1c1df..fad04d677073215b45861868a1dedb4472c2fba4 100644
--- a/chrome/browser/instant/instant_controller.cc
+++ b/chrome/browser/instant/instant_controller.cc
@@ -183,7 +183,8 @@ InstantController::InstantController(chrome::BrowserInstantController* browser,
       omnibox_focus_state_(OMNIBOX_FOCUS_NONE),
       start_margin_(0),
       end_margin_(0),
-      allow_preview_to_show_search_suggestions_(false) {
+      allow_preview_to_show_search_suggestions_(false),
+      instant_set_transient_entry_(false) {
 }
 
 InstantController::~InstantController() {
@@ -933,6 +934,8 @@ void InstantController::InstantPageAboutToNavigateMainFrame(
   if (model_.mode().is_ntp() ||
       (url.host() != instant_url.host() || url.path() != instant_url.path())) {
     CommitIfPossible(INSTANT_COMMIT_NAVIGATED);
+  } else {
+    UpdateTransientHistoryEntry(url);
   }
 }
 
@@ -1202,6 +1205,8 @@ void InstantController::HideInternal() {
     overlay_->Update(string16(), 0, 0, true);
   }
 
+  ResetTransientHistoryEntry();
+
   // Clear the first interaction timestamp for later use.
   first_interaction_time_ = base::Time();
 }
@@ -1260,6 +1265,43 @@ void InstantController::ShowOverlay(InstantShownReason reason,
   // overlay (because we're not full height).
   if (reason == INSTANT_SHOWN_CLICKED_QUERY_SUGGESTION)
     CommitIfPossible(INSTANT_COMMIT_CLICKED_QUERY_SUGGESTION);
+  else if (extended_enabled_ && IsFullHeight(model_))
+    SetTransientHistoryEntry();
+}
+
+void InstantController::SetTransientHistoryEntry() {
+  content::WebContents* active_tab = browser_->GetActiveWebContents();
+  // If the active tab already has a transient entry, leave it alone.
+  if (active_tab->GetController().GetTransientEntry())
+    return;
+  // The loader's base navigation entry should describe the search provider
+  // without reference to a specific query. The alternative, updating the query
+  // in the tab title as the user types, would be distracting.
+  const content::NavigationEntry* base_entry =
+    overlay_->base_navigation_entry();
+  DCHECK(base_entry != NULL);
+  content::NavigationEntry* transient_entry =
+      content::NavigationEntry::Create(*base_entry);
+  active_tab->GetController().AddTransientEntry(transient_entry);
+  instant_set_transient_entry_ = true;
+}
+
+void InstantController::UpdateTransientHistoryEntry(const GURL& url) {
+  // URL should update so that if the user presses reload, we reload the page
+  // for the current query, but title remains unchanged so it doesn't flicker.
+  if (instant_set_transient_entry_) {
+    content::WebContents* active_tab = browser_->GetActiveWebContents();
+    content::NavigationEntry* transient_entry =
+        active_tab->GetController().GetTransientEntry();
+    DCHECK(transient_entry != NULL);
+    transient_entry->SetURL(url);
+    transient_entry->SetVirtualURL(url);
+  }
+}
+
+void InstantController::ResetTransientHistoryEntry() {
+  // NavigationController will discard the entry.
+  instant_set_transient_entry_ = false;
 }
 
 void InstantController::SendPopupBoundsToPage() {