InstantExtended: don't preload the local NTP.

In local-only mode, don't bother preloading the Instant NTP. The speed savings
of preloading a local page are minimal and this will help reduce the memory
usage.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/14232007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194982 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/search/instant_controller.cc

@@ -220,7 +220,7 @@ InstantController::InstantController(BrowserInstantController* browser,
     : browser_(browser),
       extended_enabled_(extended_enabled),
       instant_enabled_(false),
-      use_local_overlay_only_(true),
+      use_local_page_only_(true),
       model_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
       last_omnibox_text_has_inline_autocompletion_(false),
       last_verbatim_(false),
@@ -504,8 +504,16 @@ scoped_ptr<content::WebContents> InstantController::ReleaseNTPContents() {
 
   scoped_ptr<content::WebContents> ntp_contents = ntp_->ReleaseContents();
 
-  // Override the blacklist on an explicit user action.
-  ResetNTP(true, false);
+  if (!use_local_page_only_) {
+    // Preload a new Instant NTP, unless using the local NTP which is not
+    // preloaded to conserve memory.
+    //
+    // Since this corresponds to a user action, give the remote page another
+    // try, even if it's blacklisted. We don't want to blacklist pages for the
+    // duration of a Browser object (for some people, that's effectively
+    // "forever").
+    ResetNTP(true, false);
+  }
   return ntp_contents.Pass();
 }
 
@@ -887,26 +895,33 @@ void InstantController::TabDeactivated(content::WebContents* contents) {
 }
 
 void InstantController::SetInstantEnabled(bool instant_enabled,
-                                          bool use_local_overlay_only) {
+                                          bool use_local_page_only) {
   LOG_INSTANT_DEBUG_EVENT(this, base::StringPrintf(
-      "SetInstantEnabled: instant_enabled=%d, use_local_overlay_only=%d",
-      instant_enabled, use_local_overlay_only));
+      "SetInstantEnabled: instant_enabled=%d, use_local_page_only=%d",
+      instant_enabled, use_local_page_only));
 
-  // Non extended mode does not care about |use_local_overlay_only|.
+  // Non extended mode does not care about |use_local_page_only|.
   if (instant_enabled == instant_enabled_ &&
       (!extended_enabled_ ||
-       use_local_overlay_only == use_local_overlay_only_)) {
+       use_local_page_only == use_local_page_only_)) {
     return;
   }
 
   instant_enabled_ = instant_enabled;
-  use_local_overlay_only_ = use_local_overlay_only;
+  use_local_page_only_ = use_local_page_only;
   HideInternal();
   overlay_.reset();
   if (extended_enabled_ || instant_enabled_)
     EnsureOverlayIsCurrent(false);
-  if (extended_enabled_)
-    ResetNTP(false, false);
+  if (extended_enabled_) {
+    // Preload the Instant NTP. But if we are using the local NTP, delete any
+    // existing preloaded NTP (which we should no longer use) and don't preload
+    // the local one to conserve memory.
+    if (use_local_page_only_)
+      ntp_.reset();
+    else
+      ResetNTP(false, false);
+  }
   if (instant_tab_)
     instant_tab_->SetDisplayInstantResults(instant_enabled_);
 }
@@ -1449,7 +1464,7 @@ void InstantController::SendPopupBoundsToPage() {
 bool InstantController::GetInstantURL(Profile* profile,
                                       bool ignore_blacklist,
                                       std::string* instant_url) const {
-  if (extended_enabled_ && use_local_overlay_only_)
+  if (extended_enabled_ && use_local_page_only_)
     return false;
 
   const GURL instant_url_obj = chrome::GetInstantURL(profile,

chrome/browser/ui/search/instant_controller.h

@@ -154,10 +154,10 @@ class InstantController : public InstantPage::Delegate,
   // The user is about to switch tabs. Commit the overlay if needed.
   void TabDeactivated(content::WebContents* contents);
 
-  // Sets whether Instant should show result overlays. |use_local_overlay_only|
-  // will force the use of kLocalOmniboxPopupURL as the Instant URL and is only
+  // Sets whether Instant should show result overlays. |use_local_page_only|
+  // will force the use of baked-in page as the Instant URL and is only
   // applicable if |extended_enabled_| is true.
-  void SetInstantEnabled(bool instant_enabled, bool use_local_overlay_only);
+  void SetInstantEnabled(bool instant_enabled, bool use_local_page_only);
 
   // The theme has changed. Pass the message to the overlay page.
   void ThemeChanged(const ThemeBackgroundInfo& theme_info);
@@ -223,7 +223,7 @@ class InstantController : public InstantPage::Delegate,
   FRIEND_TEST_ALL_PREFIXES(InstantExtendedTest, ValidatesSuggestions);
   FRIEND_TEST_ALL_PREFIXES(InstantExtendedTest,
                            OmniboxCommitsWhenShownFullHeight);
-  FRIEND_TEST_ALL_PREFIXES(InstantExtendedTest, LocalNTPIsNotLocalOverlay);
+  FRIEND_TEST_ALL_PREFIXES(InstantExtendedTest, LocalNTPIsNotPreloaded);
   FRIEND_TEST_ALL_PREFIXES(InstantExtendedManualTest,
                            MANUAL_OmniboxFocusLoadsInstant);
 
@@ -377,7 +377,7 @@ class InstantController : public InstantPage::Delegate,
   bool instant_enabled_;
 
   // If true, the Instant URL is set to kLocalOmniboxPopupURL.
-  bool use_local_overlay_only_;
+  bool use_local_page_only_;
 
   // The state of the overlay page, i.e., the page owned by |overlay_|. Ignored
   // if |instant_tab_| is in use.

chrome/browser/ui/search/instant_extended_browsertest.cc

@@ -1482,17 +1482,16 @@ IN_PROC_BROWSER_TEST_F(InstantExtendedTest, AutocompleteProvidersDone) {
   EXPECT_EQ(1, on_native_suggestions_calls_);
 }
 
-// Test that the local NTP doesn't end up with the local overlay's URL.
-IN_PROC_BROWSER_TEST_F(InstantExtendedTest, LocalNTPIsNotLocalOverlay) {
+// Test that the local NTP is not preloaded.
+IN_PROC_BROWSER_TEST_F(InstantExtendedTest, LocalNTPIsNotPreloaded) {
   ASSERT_NO_FATAL_FAILURE(SetupInstant(browser()));
 
   EXPECT_EQ(instant_url(), instant()->ntp_->contents()->GetURL());
 
-  // The second argument says to use only the local overlay.
+  // The second argument says to use only the local overlay and NTP.
   instant()->SetInstantEnabled(false, true);
 
-  EXPECT_EQ(GURL(chrome::kChromeSearchLocalNtpUrl),
-            instant()->ntp_->contents()->GetURL());
+  EXPECT_EQ(NULL, instant()->ntp());
 }
 
 // Verify top bars visibility when searching on |DEFAULT| pages and switching