[extensions] Don't let clicks on <a href="#"> links escape un-prevented.

Also adds the utility to stop clicks on any page to util.js and makes the NTP a
user of this function.

BUG=136338
TEST=Inspect a background view, options, or reload an extension while scrolled
without being forced to the top of the page.

Review URL: https://chromiumcodereview.appspot.com/10832196

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151127 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/extensions/extensions.html

@@ -18,6 +18,7 @@
 <script src="chrome://resources/js/util.js"></script>
 <script src="chrome://resources/js/cr/ui.js"></script>
 <script src="chrome://resources/js/cr/ui/alert_overlay.js"></script>
+<script src="chrome://resources/js/cr/ui/drag_wrapper.js"></script>
 <script src="chrome://resources/js/cr/ui/focus_manager.js"></script>
 <script src="chrome://resources/js/cr/ui/overlay.js"></script>
 

chrome/browser/resources/extensions/extensions.js

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-<include src="../shared/js/cr/ui/drag_wrapper.js"></include>
 <include src="../uber/uber_utils.js"></include>
 <include src="extension_commands_overlay.js"></include>
 <include src="extension_focus_manager.js"></include>
@@ -116,6 +115,8 @@ cr.define('extensions', function() {
       cr.ui.overlay.setupOverlay($('dropTargetOverlay'));
 
       extensions.ExtensionFocusManager.getInstance().initialize();
+
+      preventDefaultOnPoundLinkClicks();  // From shared/js/util.js.
     },
 
     /**
@@ -151,7 +152,6 @@ cr.define('extensions', function() {
       ExtensionSettings.showOverlay($('extensionCommandsOverlay'));
       chrome.send('coreOptionsUserMetricsAction',
                   ['Options_ExtensionCommands']);
-      e.preventDefault();
     },
 
     /**

chrome/browser/resources/ntp4/new_tab.js

@@ -212,6 +212,8 @@ cr.define('ntp', function() {
       cr.dispatchSimpleEvent(document, 'ntpLoaded', true, true);
       document.documentElement.classList.remove('starting-up');
     });
+
+    preventDefaultOnPoundLinkClicks();  // From shared/js/util.js.
   }
 
   /**

chrome/browser/resources/shared/js/util.js

@@ -128,6 +128,17 @@ function disableTextSelectAndDrag(opt_allowSelectStart, opt_allowDragStart) {
   };
 }
 
+/**
+ * Call this to stop clicks on <a href="#"> links from scrolling to the top of
+ * the page (and possibly showing a # in the link).
+ */
+function preventDefaultOnPoundLinkClicks() {
+  document.addEventListener('click', function(e) {
+    if (e.target.nodeName == 'A' && e.target.getAttribute('href') == '#')
+      e.preventDefault();
+  });
+}
+
 /**
  * Check the directionality of the page.
  * @return {boolean} True if Chrome is running an RTL UI.