Here is a really cool plugin. http://lab.maltewassermann.com/viewport-resizer/
You can use it on any browser. Drag the "Click or Bookmark" button to your bookmark bar, then click it on any page you want to change the view size for.
Here is the image of the button you want to drag to your bookmark bar:
Here is an image of the toolbar that it adds.
My favorite tool to use for this is http://www.browserstack.com/. This isn't free but well worth it.
A third option is Adobe Edge Inspect. You can display the page right on the device but inspect the elements through you laptop or desktop computer. This option is free but you need to create an Adobe ID.