Mac: Prevent NTP mousewheel events from being suppressed on Lion.

chrome/browser/ui/webui/ntp/ntp_resource_cache.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/ui/webui/ntp/ntp_resource_cache.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
@@ skipping 40 matching lines @@
 #include "ui/gfx/sys_color_change_listener.h"
 
 #if defined(OS_WIN) || defined(TOOLKIT_VIEWS)
 #include "chrome/browser/ui/views/bookmarks/bookmark_bar_view.h"
 #elif defined(OS_MACOSX)
 #include "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_constants.h"
 #elif defined(TOOLKIT_GTK)
 #include "chrome/browser/ui/gtk/bookmarks/bookmark_bar_gtk.h"
 #endif
 
+#if defined(OS_MACOSX)
+#include "chrome/browser/platform_util.h"
+#endif
+
 using base::Time;
 using content::BrowserThread;
 
 namespace {
 
 // The URL for the the Learn More page shown on incognito new tab.
 const char kLearnMoreIncognitoUrl[] =
 #if defined(OS_CHROMEOS)
     "https://www.google.com/support/chromeos/bin/answer.py?answer=95464";
 #else
@@ skipping 117 matching lines @@
   // Watch for pref changes that cause us to need to invalidate the HTML cache.
   pref_change_registrar_.Init(profile_->GetPrefs());
   pref_change_registrar_.Add(prefs::kSyncAcknowledgedSyncTypes, this);
   pref_change_registrar_.Add(prefs::kShowBookmarkBar, this);
   pref_change_registrar_.Add(prefs::kNtpShownPage, this);
   pref_change_registrar_.Add(prefs::kSyncPromoShowNTPBubble, this);
 }
 
 NTPResourceCache::~NTPResourceCache() {}
 
+bool NTPResourceCache::NewTabCacheNeedsRefresh() {
+#if defined(OS_MACOSX)
+  // Invalidate if the current value is different from the cached value.
+  bool is_enabled = platform_util::IsSwipeTrackingFromScrollEventsEnabled();
+  if (is_enabled != is_swipe_tracking_from_scroll_events_enabled_) {
+    is_swipe_tracking_from_scroll_events_enabled_ = is_enabled;
+    return true;
+  }
+#endif
+  return false;
+}
+
 RefCountedMemory* NTPResourceCache::GetNewTabHTML(bool is_incognito) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (is_incognito) {
     if (!new_tab_incognito_html_.get())
       CreateNewTabIncognitoHTML();
   } else {
-    if (!new_tab_html_.get())
+    // Refresh the cached HTML if necessary.
+    // NOTE: NewTabCacheNeedsRefresh() must be called every time the new tab
+    // HTML is fetched, because it needs to initialize cached values.
+    if (NewTabCacheNeedsRefresh() || !new_tab_html_.get())
       CreateNewTabHTML();
   }
   return is_incognito ? new_tab_incognito_html_.get() :
                         new_tab_html_.get();
 }
 
 RefCountedMemory* NTPResourceCache::GetNewTabCSS(bool is_incognito) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (is_incognito) {
     if (!new_tab_incognito_css_.get())
@@ skipping 143 matching lines @@
   localized_strings.SetBoolean("appInstallHintEnabled",
       NewTabUI::ShouldShowAppInstallHint());
   localized_strings.SetString("appInstallHintText",
       l10n_util::GetStringUTF16(IDS_NEW_TAB_APP_INSTALL_HINT_LABEL));
   localized_strings.SetBoolean("isSuggestionsPageEnabled",
       NewTabUI::IsSuggestionsPageEnabled());
   localized_strings.SetBoolean("showApps", NewTabUI::ShouldShowApps());
   localized_strings.SetString("hideSessionMenuItemText",
       l10n_util::GetStringUTF16(IDS_POLICY_HIDE));
 
+  // On Mac OS X 10.7+, horizontal scrolling can be treated as a back or
+  // forward gesture. Pass through a flag that indicates whether or not that
+  // feature is enabled.
+  localized_strings.SetBoolean("isSwipeTrackingFromScrollEventsEnabled",
+                               is_swipe_tracking_from_scroll_events_enabled_);
+
 #if defined(OS_CHROMEOS)
   localized_strings.SetString("expandMenu",
       l10n_util::GetStringUTF16(IDS_NEW_TAB_CLOSE_MENU_EXPAND));
 #endif
 
   NewTabPageHandler::GetLocalizedValues(profile_, &localized_strings);
   NTPLoginHandler::GetLocalizedValues(profile_, &localized_strings);
 
   // Don't initiate the sync related message passing with the page if the sync
   // code is not present.
@@ skipping 174 matching lines @@
   // Get our template.
   static const base::StringPiece new_tab_theme_css(
       ResourceBundle::GetSharedInstance().GetRawDataResource(
           IDR_NEW_TAB_4_THEME_CSS));
 
   // Create the string from our template and the replacements.
   std::string css_string;
   css_string = ReplaceStringPlaceholders(new_tab_theme_css, subst, NULL);
   new_tab_css_ = base::RefCountedString::TakeString(&css_string);
 }