DevTools: Introduce ThreadsSidebar

BUG=

Review URL: https://codereview.chromium.org/449893002

git-svn-id: svn://svn.chromium.org/blink/trunk@179827 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Range.insertNode should verify parent before setting end to it

This is because ContainerNode::insertBefore would cause mutation in tree.
So this CL adds code block to throw exception if parent is not avaiable.
In addition, http://crbug.com/399230 will be fixed with this CL.

BUG=399230
TEST=LayoutTests/fast/dom/Range/surroundContents-for-mutation.html

Review URL: https://codereview.chromium.org/443103002

git-svn-id: svn://svn.chromium.org/blink/trunk@179828 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Get rid of CSS hackery in CanvasProfiler.

The CSS that we use to center the replay image is broken again.
Remove it in favor of JavaScript.

R=vsevik

Review URL: https://codereview.chromium.org/446763003

git-svn-id: svn://svn.chromium.org/blink/trunk@179829 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Create "Paint profiler" experiment

In preparation to moving "Timeline on traced events" out of experimentat created a separate experiment for "Paint profiler".

BUG=399531
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/455773002

git-svn-id: svn://svn.chromium.org/blink/trunk@179830 bbb929c8-8fbe-4397-9dbb-9b2b20218538