Webkit: fix browser can't display italic font in WCSS page

With no knowledge of the actual SkTypeface used to render
text before render-time, the best we can do is turn fake
italic on for all text and simply ignore it at render-time
if the SkTypeface's style is italic.

Also the complex FontPlatformData hashing mechanism needed
to account for fake styles, as the versions of FontPlatformData
with fake styles enabled are otherwise indistinguishable from the
normal style version.

CRs-Fixed: 580264

Change-Id: Iaf0a621b954739345772c022190f9dbf3c2a5afa
MIMETypeRegistry.cpp: add support for the DASH mimetype

Without this entry the Android browser plays DASH video in situ.  The
browser should instead launch Video Player.

Change-Id: Iafd1743e6aac07f2c9be69358f7ebd69dbdab20c
CRs-Fixed: 539815