Support font-variant-ligatures: (no-)contextual.

BUG=348659

Review URL: https://codereview.chromium.org/189163004

git-svn-id: svn://svn.chromium.org/blink/trunk@168764 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Extract font weight to traits mask conversion into utility functions

Extract the logic for converting between a font weight and a traits
mask into utility functions and use those instead of manipulating the
masks directly. This is the first step towards changing how we store
weights in the mask.

R=eseidel@chromium.org
BUG=

Review URL: https://codereview.chromium.org/189713003

git-svn-id: svn://svn.chromium.org/blink/trunk@168765 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Moved PinchViewport from Source/web to Souce/core/frame.

BUG=349941

Review URL: https://codereview.chromium.org/189823002

git-svn-id: svn://svn.chromium.org/blink/trunk@168766 bbb929c8-8fbe-4397-9dbb-9b2b20218538