Implement autosizing for <extensionoptions>

chrome/browser/guest_view/extension_options/extension_options_constants.cc

 // Copyright 2014 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/guest_view/extension_options/extension_options_constants.h"
 
 namespace extensionoptions {
 
+// Attributes.
+const char kAttributeAutoSize[] = "autosize";
+const char kAttributeMaxHeight[] = "maxheight";
+const char kAttributeMaxWidth[] = "maxwidth";
+const char kAttributeMinHeight[] = "minheight";
+const char kAttributeMinWidth[] = "minwidth";
+
 const char kExtensionId[] = "extensionId";
+const char kHeight[] = "height";
+const char kWidth[] = "width";
 
 }  // namespace extensionoptions