Oilpan: Prepare to move UA shadow elemnts for date/time input types to Oilpan heap.

This CL is a preparation to move the following classes:

- DateTimeEditElement

- DateTimeEditElement::EditControlOwner as GarbageCollectedMixin
  BaseMultipleFieldsDateAndTimeInputType implements it.

- DateTimeFieldElement and its subclasses

- DateTimeFieldElement::FieldOwner as GarbageCollectedMixin
  DateTimeEditElement implements it.

BUG=357163

Review URL: https://codereview.chromium.org/267413002

git-svn-id: svn://svn.chromium.org/blink/trunk@173533 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Layout Test fast/dom/StyleSheet/gc-declaration-parent-rule.html is failing

BUG=370906
TBR=wibling@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/274453006

git-svn-id: svn://svn.chromium.org/blink/trunk@173534 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove layers above content root from LayerTree.

Review URL: https://codereview.chromium.org/269303005

Review URL: https://codereview.chromium.org/269303005

git-svn-id: svn://svn.chromium.org/blink/trunk@173535 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Update warning UI.

BUG=370804

Review URL: https://codereview.chromium.org/274583004

git-svn-id: svn://svn.chromium.org/blink/trunk@173536 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Each LayoutTest shouldn't register SW for root/top-level scope

Currently registering something for a global scope could make
other tests fail due to issue 370773, let's always use
narrower scope and unregister the scope before the test runs.

(We'll need to have longest-prefix-match tests separately when
we fix the bug)

BUG=370777
TEST=http/tests/serviceworker/*

Review URL: https://codereview.chromium.org/270613003

git-svn-id: svn://svn.chromium.org/blink/trunk@173537 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: REGRESSION: Profile start button is seen disabled.

BUG=369912
R=pfeldman, yurys

Review URL: https://codereview.chromium.org/273593003

git-svn-id: svn://svn.chromium.org/blink/trunk@173538 bbb929c8-8fbe-4397-9dbb-9b2b20218538