Primary FontData of FontFallbackList should have space character

This patch makes FontFallbackList::primaryFontData() skips
SegmentedFontData that does not have space character.
FontFallbackList::primarySimpleFontData() expects primaryFontData has
FontData for space character.

This prevents @font-face with unicode-range outside space character
(for example, overrides only an ampersand) from being downloaded
unnecessarily, and used as primary font.

BUG=247920
TEST=fast/css/font-face-unicode-range-load.html

Review URL: https://codereview.chromium.org/162883002

git-svn-id: svn://svn.chromium.org/blink/trunk@167130 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Associate DisableCompositingQueryAsserts instances with bugs

BUG=282720
TBR=esprehn@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/165693002

git-svn-id: svn://svn.chromium.org/blink/trunk@167131 bbb929c8-8fbe-4397-9dbb-9b2b20218538