Create movementX/Y on MouseEvent.

Part of the larger task of creating an unprefixed Pointer Lock API.
Intent to Implement and Ship approved April 21 2014
http://goo.gl/uQTJjH.

BUG=359738

Review URL: https://codereview.chromium.org/281383010

git-svn-id: svn://svn.chromium.org/blink/trunk@175081 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Correctly handle object classname and add Symbol type to PropertyPreview and CallArgument in the protocol.

BUG=376194

Review URL: https://codereview.chromium.org/303113002

git-svn-id: svn://svn.chromium.org/blink/trunk@175082 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: brush up responsive design toolbar css.

Review URL: https://codereview.chromium.org/307973002

git-svn-id: svn://svn.chromium.org/blink/trunk@175083 bbb929c8-8fbe-4397-9dbb-9b2b20218538