[WebUI] Make drag'n'drop future proof.

TEST=Drag and drop from external sources works on NTP and net-internals.
BUG=115433


Review URL: http://codereview.chromium.org/9596003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@125109 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/net_internals/import_view.js

@@ -80,7 +80,13 @@ var ImportView = (function() {
      * security reasons, which is why we allow the |files| array to be empty.
      */
     onDrag: function(event) {
-      return !event.dataTransfer.types.contains('Files') ||
+      // NOTE: Use Array.prototype.indexOf here is necessary while WebKit
+      // decides which type of data structure dataTransfer.types will be
+      // (currently between DOMStringList and Array). These have different APIs
+      // so assuming one type or the other was breaking things. See
+      // http://crbug.com/115433. TODO(dbeam): Remove when standardized more.
+      var indexOf = Array.prototype.indexOf;
+      return indexOf.call(event.dataTransfer.types, 'Files') == -1 ||
              event.dataTransfer.files.length > 1;
     },
 
@@ -89,7 +95,8 @@ var ImportView = (function() {
      * file, tries to load it as a log file.
      */
     onDrop: function(event) {
-      if (!event.dataTransfer.types.contains('Files') ||
+      var indexOf = Array.prototype.indexOf;
+      if (indexOf.call(event.dataTransfer.types, 'Files') == -1 ||
           event.dataTransfer.files.length != 1) {
         return;
       }

chrome/browser/resources/ntp4/apps_page.js

@@ -790,8 +790,12 @@ cr.define('ntp', function() {
 
     /** @inheritDoc */
     shouldAcceptDrag: function(e) {
-      return !!ntp.getCurrentlyDraggingTile() ||
-          (e.dataTransfer && e.dataTransfer.types.contains('text/uri-list'));
+      if (ntp.getCurrentlyDraggingTile())
+        return true;
+      if (!e.dataTransfer || !e.dataTransfer.types)
+        return false;
+      return Array.prototype.indexOf.call(e.dataTransfer.types,
+                                          'text/uri-list') != -1;
     },
 
     /** @inheritDoc */