Introduce DEFINE_FONT_DATA_TYPE_CASTS, and use it

As a step to use toFoo, this cl introduces DEFINE_FONT_DATA_TYPE_CASTS, and use it.
In SegmentedFontData case, it already has own type cast macro. This cl removes it, and use
DEFINE_FONT_DATA_TYPE_CASTS.

BUG=309516

Review URL: https://codereview.chromium.org/401553002

git-svn-id: svn://svn.chromium.org/blink/trunk@178332 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unneeded ASSERT in StyleResolver::styleSharingList

Remove unneeded ASSERT in StyleResolver::styleSharingList, the unsigned can't be negative so don't check for it.

Review URL: https://codereview.chromium.org/396343002

git-svn-id: svn://svn.chromium.org/blink/trunk@178333 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unused and redundant CSSProperties.in flags

This patch removes redundant flags from properties in CSSProperties.in
(that match the default value the python script will guess), and lots of
unused type_name flags. There are no plans currently to make use of the
type_name flag outside of the StyleBuilder so having these values set
isn't much use to us (it's used in the default value handler and where
explicitly referred to in generated custom handlers).

BUG=374530

Review URL: https://codereview.chromium.org/395053002

git-svn-id: svn://svn.chromium.org/blink/trunk@178334 bbb929c8-8fbe-4397-9dbb-9b2b20218538
axObjectCache() can return null.

BUG=373300

Review URL: https://codereview.chromium.org/394123004

git-svn-id: svn://svn.chromium.org/blink/trunk@178335 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: NetworkPanel: do not reset linkifier until node is alive.

This patch is a preparation to butter-smooth viewport in NetworkPanel.

BUG=

Review URL: https://codereview.chromium.org/398763002

git-svn-id: svn://svn.chromium.org/blink/trunk@178336 bbb929c8-8fbe-4397-9dbb-9b2b20218538