Disable deferred image decoding for GIFs due to performance regression

Temporarily the feature of defer decoding multi-frame images.

TBR=senorblanco@chromium.org
BUG=260052

Review URL: https://chromiumcodereview.appspot.com/19634006

git-svn-id: svn://svn.chromium.org/blink/trunk@154726 bbb929c8-8fbe-4397-9dbb-9b2b20218538
&zwj; and &zwnj; should not be treated as missing glyphs.

This is for fixing the regression I introduced in r153776, which meant to be
a workaround against Windows Vista that sometimes return zero-width glyph for
a missing glyph. However, obviously, truely zero-width characters should not
be regarded as missing glyphs. Most of such characters were already excepted out,
but &zwj; and &zwnj; were not handled.

BUG=262113, 120336

Review URL: https://chromiumcodereview.appspot.com/20019002

git-svn-id: svn://svn.chromium.org/blink/trunk@154727 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert "USERSELECT_ALL flag is removed and the feature is enabled."

r154244 caused a regression breaking text selection in Yahoo Mail.

This reverts commit 8561674657274e9edc16f13a75b0940b22868281.

R=ojan@chromium.org
BUG=262136

Review URL: https://chromiumcodereview.appspot.com/20002006

git-svn-id: svn://svn.chromium.org/blink/trunk@154728 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Refactoring: Extract Document::processHttpEquivContentSecurityPolicy().

BUG=none
TEST=none
R=mkwst@chromium.org

Review URL: https://chromiumcodereview.appspot.com/19958004

git-svn-id: svn://svn.chromium.org/blink/trunk@154729 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove virual RenderFlexibleBox::computePreferredLogicalWidths()

RenderFlexibleBox does not need this duplicated code from RenderBlock.
This patch removes the overridden function.

Note that RenderFlexibleBox will now go through the
updateFirstLetter() check but first letter is disabled for
flexible box and this call is short-circuited immediately
in RenderBlock::updateFirstLetter()

BUG=263225

Review URL: https://chromiumcodereview.appspot.com/19631006

git-svn-id: svn://svn.chromium.org/blink/trunk@154730 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Switch lots of appendChild callers to AttachLazily

This switches most callers of appendChild to lazy attach. I left TextTrackCues since it looks
like it might need some more substantial refactoring and everything related to editing since
that code is more fragile.

This is part of making everything lazy attach, but I'm doing it slowly in steps to isolate
breakages and expose parts of the code that were making bad assumptions about when renderers
were created.

R=eseidel@chromium.org,ojan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/19134002

git-svn-id: svn://svn.chromium.org/blink/trunk@154731 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add a comment for HTMLInputElement.files attribute

Add a comment for HTMLInputElement.files attribute to explain that
it is intentionally not marked as readonly because of:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=22682

NOTRY=true
R=tkent
BUG=263060

Review URL: https://chromiumcodereview.appspot.com/19963003

git-svn-id: svn://svn.chromium.org/blink/trunk@154732 bbb929c8-8fbe-4397-9dbb-9b2b20218538