Add a UseCounter for SVGUseElement.instanceRoot

This patch adds a UseCounter for instanceRoot, the accessor for the
SVG instance tree. This patch does not add a usecounter for
SVGUseElement.animatedInstanceRoot because it is not suported
(see: SVGUseElement::animatedInstanceRoot)

BUG=313438

Review URL: https://codereview.chromium.org/54053002

git-svn-id: svn://svn.chromium.org/blink/trunk@161021 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Web Animations: Support animation of line-height

BUG=257591

Review URL: https://codereview.chromium.org/26492005

git-svn-id: svn://svn.chromium.org/blink/trunk@161022 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Handle line-height values that are calcs

Add a case for calc values in StyleBuilderFunctions::applyValueCSSPropertyLineHeight.

Add test cases to /LayoutTests/css3/calc/line-height.html to cover zoom and calc with ems.

Simplify valueForLineHeight in CSSComputedStyleDeclaration.cpp. This changes behavior so that line-heights are not rounded to integers.

Remove test for line-height rounding. Only percents were rounded previously; with this change nothing is rounded. Rounding isn't mentioned in the specs & Firefox does not round. Original discussion is here: https://bugs.webkit.org/show_bug.cgi?id=24434

BUG=287882

Review URL: https://codereview.chromium.org/50683004

git-svn-id: svn://svn.chromium.org/blink/trunk@161023 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Overrides section is incompletely shown in developer tools

BUG=313160

TBR=vsevik

Review URL: https://codereview.chromium.org/54103002

git-svn-id: svn://svn.chromium.org/blink/trunk@161024 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Turn on -Werror on all non-Win platforms.

Part of the patch by mithro@mithis.com, that part reviewed at
https://codereview.chromium.org/47023014

BUG=312287
R=dglazkov@chromium.org
TBR=dglazkov
NOTRY=true

Review URL: https://codereview.chromium.org/50253002

git-svn-id: svn://svn.chromium.org/blink/trunk@161025 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: [Default] arguments

V. widely used.
Long-term we should instead use the Web IDL standard:
optional type identifier = value
instead of
[Default=value] optional type identifier
...which is much cleaner and clearer,
but that requires parser support and isn't worth doing in Perl.

Docs:
http://www.w3.org/TR/WebIDL/#dfn-optional-argument-default-value
https://sites.google.com/a/chromium.org/dev/blink/webidl/blink-idl-extended-attributes#TOC-Default-p-

BUG=239771
NOTRY=true

Review URL: https://codereview.chromium.org/47023015

git-svn-id: svn://svn.chromium.org/blink/trunk@161026 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add font scale factor override to the inspector.

The font scale factor provided by the Android system is important for
accurate text sizing. This patch adds this setting back to the
viewport overrides section of the inspector, and correctly computes it
on a per-device setting.

This improves autosizing behavior so that sites are almost exactly as
they appear on the real device.

BUG=302005

Review URL: https://codereview.chromium.org/50343002

git-svn-id: svn://svn.chromium.org/blink/trunk@161027 bbb929c8-8fbe-4397-9dbb-9b2b20218538