Worker threads should be registered to task observers

r179309 switched the implementation of worker threads to
web threads. This caused timeout in a lot of worker tests
in oilpan builds. This is because the worker threads
were not registered to task observers, and thus the
worker threads didn't enter safe points at the end of
each task execution.

This CL registers worker threads to task observers
and fixes the issue. 

BUG=399762

Review URL: https://codereview.chromium.org/441653002

git-svn-id: svn://svn.chromium.org/blink/trunk@179463 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Decouple debugger model from UI entities

DebuggerPresentationModel has been introduced in order to
- manage source mappings,
- store live locations,
- perform the rawLocationToUILocation conversions.

RawLocation.uiLocation() has been removed.

This patch depends on https://codereview.chromium.org/297923002/
R=pfeldman, vsevik

Review URL: https://codereview.chromium.org/299443016

git-svn-id: svn://svn.chromium.org/blink/trunk@179464 bbb929c8-8fbe-4397-9dbb-9b2b20218538
LeakDetector: Add a new expectation for resolve-after-window-close.html


BUG=400012
TEST=n/a
NOTRY=true

Review URL: https://codereview.chromium.org/437213003

git-svn-id: svn://svn.chromium.org/blink/trunk@179465 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: AutoConnect to workers by default in WorkersInMainFrontend experiment

BUG=

Review URL: https://codereview.chromium.org/370303002

git-svn-id: svn://svn.chromium.org/blink/trunk@179466 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Get rid of a sync callback in UISourceCode#commitWorkingCopy()

This is a leftover from UISC refactorings and no longer makes sense.

R=sergeyv, vsevik

Review URL: https://codereview.chromium.org/433073002

git-svn-id: svn://svn.chromium.org/blink/trunk@179467 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix the memory leak in test case RawPtrInHash of blink_heap_unittests

1. Reason: running blink_heap_unittests with valgrind or Lsan will report this memory leak in report, so fix it.
2. Modification: after the check operation delete the allocated memory pointed by raw pointer in the set element.

R=haraken@chromium.org, oilpan-reviews@chromium.org
BUG=397452

Review URL: https://codereview.chromium.org/423563003

git-svn-id: svn://svn.chromium.org/blink/trunk@179468 bbb929c8-8fbe-4397-9dbb-9b2b20218538