Files app: fix "Buy more storage" link in the low Drive space warning

BUG=169049

Review URL: https://codereview.chromium.org/11827050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176071 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/file_manager/js/drive_banners.js

@@ -282,10 +282,11 @@ FileListBannerController.prototype.showLowGDriveSpaceWarning_ =
         util.bytesToSi(sizeStats.remainingSizeKB * 1024));
     box.appendChild(text);
 
-    var link = this.document_.createElement('div');
+    var link = this.document_.createElement('a');
     link.className = 'plain-link';
     link.textContent = str('DRIVE_BUY_MORE_SPACE_LINK');
     link.href = GOOGLE_DRIVE_BUY_STORAGE;
+    link.target = '_blank';
     box.appendChild(link);
 
     var close = this.document_.createElement('div');