Fix crash caused by Canvas2DLayerBridge being referenced after destruction

BUG=344220
R=senorblanco

Review URL: https://codereview.chromium.org/171523002

git-svn-id: svn://svn.chromium.org/blink/trunk@167471 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Apply initial values in OverridesSupport.js only when these values aren't default

BUG=

Review URL: https://codereview.chromium.org/172153003

git-svn-id: svn://svn.chromium.org/blink/trunk@167472 bbb929c8-8fbe-4397-9dbb-9b2b20218538