Reduce duplication for converting font enums to CSS

This patch makes convertions for font enums in CSSComputedStyleDeclaration
just use the conversions in CSSPrimitiveValueMappings to reduce code
duplication.

The font-weights 400 and 700 are identical to normal and bolder (resp.),
so I've updated the CSSPrimitiveValueMappings conversion to match what
we currently do in CSSComputedStyleDeclaration.

Review URL: https://codereview.chromium.org/429953005

git-svn-id: svn://svn.chromium.org/blink/trunk@179288 bbb929c8-8fbe-4397-9dbb-9b2b20218538
RenderBlock::layoutPositionedObjects should use setNeedsPositionedMovementLayout

This CL swiches RenderBlock::layoutPositionedObjects from using setNeedsLayout
to setNeedsPositionedMovementLayout, as indicated by the FIXME comment and
associated bug. The test failure mentioned in the bug is no longer a problem.

BUG=350756

Review URL: https://codereview.chromium.org/414123006

git-svn-id: svn://svn.chromium.org/blink/trunk@179289 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: [tracing timeline] console.timeline based on tracing. Blink part.

The fix needs changes on the both sides, chromium and blink.
Looks like two patches, one the first for blink and the
second for chromium would be enough.

The chromium part could not be landed due to changes in protocol.

1) a new hidden command was added to the protocol
for managing tracing mode of console.timeline.
It should be removed with timeline agent.
2) two new events were introduced. Tracing.started and
Tracing.stopped so we can switch the ui into recording mode.
Unfortunately the backend part doesn't trigger stopped event
 yet because stop command to tracing agent is processing on the browser side.

The mechanics of TracingTimelineModel was switched from callbacks to the event based

the chromium side patch https://codereview.chromium.org/423283004

BUG=398787
R=yurys@chromium.org

Review URL: https://codereview.chromium.org/432433002

git-svn-id: svn://svn.chromium.org/blink/trunk@179290 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove special case for ShadowRoot in notifyNodeInserted.

ShadowRoot doesn't really want to call notifyNodeInserted, it just
wants to call insertedInto directly. This also allows making the
notifyNodeInserted private.

I also made notifyNodeRemoved private and cleaned up
ElementShadow::addShadowRoot removing some ASSERTs that didn't make
sense since they just seemed to be checking if the linked list class
was implemented properly.

Review URL: https://codereview.chromium.org/425213002

git-svn-id: svn://svn.chromium.org/blink/trunk@179291 bbb929c8-8fbe-4397-9dbb-9b2b20218538