TimelinePanel: introduce StackView and use it instead of _timelineMemorySplitter

move recordsView construction code into a private method

BUG=

Review URL: https://codereview.chromium.org/139463002

git-svn-id: svn://svn.chromium.org/blink/trunk@165152 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make the type argument to HTMLMediaElement.canPlayType non-optional

http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#htmlmediaelement

Ad-hoc testing shows that it is also non-optional in Firefox Nightly,
IE11 and Opera 12.16.

BUG=334660

Review URL: https://codereview.chromium.org/138063006

git-svn-id: svn://svn.chromium.org/blink/trunk@165153 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove MarkupAccumulator::appendNodeValue() method

Remove MarkupAccumulator::appendNodeValue() method and merge it into
MarkupAccumulator::appendText() as this is the only caller. Now that we know
the Node is actually a Text node, update the implementation to call
CharacterData::data() instead of Node::nodeValue() which is virtual.

Also update CharacterData::data() to return a const reference to avoid
unnecessary ref churn on the String.

R=esprehn, abarth

Review URL: https://codereview.chromium.org/135443003

git-svn-id: svn://svn.chromium.org/blink/trunk@165154 bbb929c8-8fbe-4397-9dbb-9b2b20218538
When exporting a HistoryItem, always export the main frame's item.

This was regressed in blink r162228, where it switched to exporting the item
for whichever frame requested the HistoryItem.

BUG=334293
TEST=WebFrameTest.ExportHistoryItemFromChildFrame

Review URL: https://codereview.chromium.org/133683007

git-svn-id: svn://svn.chromium.org/blink/trunk@165155 bbb929c8-8fbe-4397-9dbb-9b2b20218538