Speculative fix for one-time ASAN crasher.

The stack traces seem to indicate that the scrollbar was being destroyed
when the HitTestResult goes out of scope but we were keeping a raw pointer
to it and accessing it after the HitTestResult is destroyed.

BUG=358813

Review URL: https://codereview.chromium.org/237883003

git-svn-id: svn://svn.chromium.org/blink/trunk@172372 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use TracedValue where it was due

We had a couple of places that had hand-crafted JSON due to absence
of support for ConvertableToTraceFormat in blink land. This fixes
these places to use TracedValue.

BUG=

Review URL: https://codereview.chromium.org/247223007

git-svn-id: svn://svn.chromium.org/blink/trunk@172373 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert 169856 "Improve gpu texture recycling in Canvas2DLayerBri..."

> Improve gpu texture recycling in Canvas2DLayerBridge.
> 
> Changing the allocation of the initaial SkSurface in
> Canvas2DLayerBridge so that it may be taken from the GrContext
> texture pool. This should improve performance for apps that
> rely heavily on transient canvas objects.
> 
> BUG=351798
> 
> Review URL: https://codereview.chromium.org/196833006

TBR=junov@chromium.org
BUG=363342

Review URL: https://codereview.chromium.org/249383002

git-svn-id: svn://svn.chromium.org/blink/trunk@172374 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Implement WeakNodeMap

This change adds a map Node<->int which doesn't retain Node.

BUG=365682

Review URL: https://codereview.chromium.org/246903008

git-svn-id: svn://svn.chromium.org/blink/trunk@172375 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Fix tests broken by r172371

These test failures somehow failed to get caught by the try bots.

TBR=pfeldman

Review URL: https://codereview.chromium.org/249393002

git-svn-id: svn://svn.chromium.org/blink/trunk@172376 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Re-enable virtual/implsidepainting/inspector/timeline tests

BUG=298188
TBR=brianderson,pfeldman

Review URL: https://codereview.chromium.org/246253013

git-svn-id: svn://svn.chromium.org/blink/trunk@172377 bbb929c8-8fbe-4397-9dbb-9b2b20218538