Fix dynamically changing sibling rules in ShadowRoots

ShadowRoot did not correctly handle dynamic changes to :first-child,
:last-child, +, ~ and :nth-child and it's variants like Element did.
This was because the method that handled dynamic changes was in Element.

This patch moves checkForSiblingStyleChanges to ContainerNode and factors
the call to checkForEmptyStyleChange out of it since that only applies to
Elements.

TEST=fast/dom/shadow/sibling-rules-dynamic-changes.html

Review URL: https://codereview.chromium.org/242103003

git-svn-id: svn://svn.chromium.org/blink/trunk@171957 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rework SVG sizing

The basis of this change is to map explicit width and height
attributes to CSS properties, essentially promoting them to
presentation attributes. Note that implicit "100%" width and height
are not mapped.

This enables us to remove the concept of "percentage intrinsic size"
and rely on normal CSS rules to resolve percentage values.

The change has been approved by the SVG WG and the spec is being
updated. Minutes here:

http://www.w3.org/2014/04/07-svg-minutes.html#item03

Many of the -expected updates are caused by SVG size changes in turn
affecting where line breaks are inserted.

BUG=308992

Review URL: https://codereview.chromium.org/26390004

git-svn-id: svn://svn.chromium.org/blink/trunk@171958 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove some dead code from html/

Remove some dead code from html/. Several methods were defined but never used.

Review URL: https://codereview.chromium.org/241113002

git-svn-id: svn://svn.chromium.org/blink/trunk@171959 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove more dead code from core/ folder

Remove more dead code from core/ folder. Several functions were defined but
never used.

R=eseidel@chromium.org, adamk@chromium.org

Review URL: https://codereview.chromium.org/241643006

git-svn-id: svn://svn.chromium.org/blink/trunk@171960 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Lazily generate HistoryItem's serialized form state

Give HistoryItem access to the object that stores the list of form elements
with state, then generated the serialized state when state is requested.

BUG=

Review URL: https://codereview.chromium.org/239993011

git-svn-id: svn://svn.chromium.org/blink/trunk@171961 bbb929c8-8fbe-4397-9dbb-9b2b20218538