querySelector() should not match deep in the multiple shadows.

querySelector() used to match deep in the shadow trees, exposed by a test:
http://jsfiddle.net/UwFP2/1/
which is different result from when the same selector is specified in CSS.

This CL fixes it by checking if the last matched element lives in the same
TreeScope as its scoping host of querySelector().

BUG=390301
TEST=pass all existing layout tests, pass the updated layout test.

Review URL: https://codereview.chromium.org/365003003

git-svn-id: svn://svn.chromium.org/blink/trunk@177716 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: NetworkPanel: get rid of search-match map and improve UX.

BUG=

Review URL: https://codereview.chromium.org/371873004

git-svn-id: svn://svn.chromium.org/blink/trunk@177717 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Replace on-stack HashSet<Node*> with WillBeHeapHashSet<RawPtrWillBeMember<Node>>

BUG=340522

Review URL: https://codereview.chromium.org/377143002

git-svn-id: svn://svn.chromium.org/blink/trunk@177718 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Oilpan: move MHTML objects to the heap.

R=haraken@chromium.org,ager@chromium.org,tkent@chromium.org
BUG=340522

Review URL: https://codereview.chromium.org/374053002

git-svn-id: svn://svn.chromium.org/blink/trunk@177719 bbb929c8-8fbe-4397-9dbb-9b2b20218538