Remove implicit use of local fonts for families defined via @font-face

This patch removes the logic in CSSSegmentedFontFaceCache that attempts to
substitute web font faces if they are also installed locally.
This hack was introduced in https://bugs.webkit.org/show_bug.cgi?id=18863
and now works only on Mac. Windows no longer uses this since the switch to
skia (r158845).

Removing this hack since this makes @font-faces render differntly when
fonts are installed locally. Also, the CSS Fonts Module Level 3 explicitly
says that this should not happen:
http://www.w3.org/TR/css3-fonts/#font-style-matching
"""
If no faces are present for a family defined via @font-face rules, the
family should be treated as missing; matching a platform font with the
same name must not occur in this case.
"""

BUG=120453

Review URL: https://codereview.chromium.org/77243005

git-svn-id: svn://svn.chromium.org/blink/trunk@162484 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make -webkit-font-kerning actually work.

Right now, the complex text path always kerns, even with
-webkit-font-kerning:none.

This is technically tested by fast/text/font-kerning.html, but the default font
often only has TrueType kerning, which isn't supported yet (bug 41990).
I've changed the test to prefer some fonts that are widely available and
actually get kerned.

BUG=165643

Review URL: https://codereview.chromium.org/74413002

git-svn-id: svn://svn.chromium.org/blink/trunk@162485 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Stop using HistoryController::previousItem() in Internals.

This involves rewriting a few form state tests to be able to access the
relevant state on the current item instead.

BUG=321280

Review URL: https://codereview.chromium.org/59153015

git-svn-id: svn://svn.chromium.org/blink/trunk@162486 bbb929c8-8fbe-4397-9dbb-9b2b20218538