ShadowDOM styles should not match shadow host without :host.

ElementRuleCollector::ruleMatches should check whether a given selector is compound and has :host
when both a given element and scope are the same shadow host.

BUG=274064
TEST=Existing layout tests cover this change.

Review URL: https://chromiumcodereview.appspot.com/25204002

git-svn-id: svn://svn.chromium.org/blink/trunk@158523 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add forEach() to CSSVariablesMap

This adds an implementation of forEach from WebIDL MapClass to
CSSVariablesMap.

Specification:
http://dev.w3.org/2006/webapi/WebIDL/#MapClass
http://dev.w3.org/csswg/css-variables/#the-CSSVariablesMap-interface

BUG=231791

Review URL: https://chromiumcodereview.appspot.com/21006006

git-svn-id: svn://svn.chromium.org/blink/trunk@158524 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add a comment about ownership to WebThread::post{Delayed,}Task

R=abarth@chromium.org

Review URL: https://chromiumcodereview.appspot.com/25198003

git-svn-id: svn://svn.chromium.org/blink/trunk@158526 bbb929c8-8fbe-4397-9dbb-9b2b20218538
MediaStream API: Updating NavigatorUserMediaError
Updating NavigatorUserMediaError both to reflect the latest spec but also
to make it a bit cleaner.

This patch has been committed as r157697 and rolled out as r157752 due to
failing browser_tests. The tests have now been updated to accept both the
new and the old error name.

BUG=294145

Review URL: https://chromiumcodereview.appspot.com/24541002

git-svn-id: svn://svn.chromium.org/blink/trunk@158527 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[DevTools] Enable deleting of a snippet by pressing delete key

This patch enables deleting a snippet by pressing delete key.
Currently to delete a snippet one has to right click and
click on 'Remove' option of the context menu.

R=pfeldman

Review URL: https://chromiumcodereview.appspot.com/25029002

git-svn-id: svn://svn.chromium.org/blink/trunk@158528 bbb929c8-8fbe-4397-9dbb-9b2b20218538