DevTools: Support CPU profiling for workers started during timeline recording

BUG=363976

Review URL: https://codereview.chromium.org/758853003

git-svn-id: svn://svn.chromium.org/blink/trunk@186130 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: [SSP] use Sets and Maps instead of objects for used properties

Use native Set/Map data structures instead of objects for
computing and storing used properties.

R=vsevik

Review URL: https://codereview.chromium.org/765813003

git-svn-id: svn://svn.chromium.org/blink/trunk@186135 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: bring back FirstPaint records (again)

- introduce CommitLoad trace event emitted together with
    InspectorInstrumentation::didCommitLoad;
- consider first DrawFrame that happens after first CompositeLayers
    that follows the last CommitLoad event to be first paint;
- use sorted flow of all inspected target events to properly
    determine relevant DrawFrame since it happens on a thread different
    from that of other events.

BUG=

Review URL: https://codereview.chromium.org/766733002

git-svn-id: svn://svn.chromium.org/blink/trunk@186136 bbb929c8-8fbe-4397-9dbb-9b2b20218538