[DevTools] Listen for "mouseup" on the top document when dragging.

It turned out that "mouseup" is not dispatched to iframe when it happens
outside of the window. This breaks dragging code.

BUG=434986

Review URL: https://codereview.chromium.org/749263004

git-svn-id: svn://svn.chromium.org/blink/trunk@185895 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[DevTools] Increase maximum emulated device size to 9999.

BUG=421397

Review URL: https://codereview.chromium.org/751013002

git-svn-id: svn://svn.chromium.org/blink/trunk@185897 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Bring treeoutline.js contents in line with the common type organization

Both TreeOutline and TreeElement have been made to inherit TreeContainerNode (to enable code reuse across these classes).

R=pfeldman
NOTRY=true

Review URL: https://codereview.chromium.org/752553002

git-svn-id: svn://svn.chromium.org/blink/trunk@185898 bbb929c8-8fbe-4397-9dbb-9b2b20218538