MQParser memory leak fix

The MQParser failed to free CSSParserValues when a MediaQuery included more than one MediaQueryExpressions.
This CL fixes that.

BUG=369417

Review URL: https://codereview.chromium.org/277433002

git-svn-id: svn://svn.chromium.org/blink/trunk@173547 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Modify BMP alpha decoding to be more similar to other browsers.

This results in ignoring the alpha channel data more often.

BUG=38618
TEST=none
R=senorblanco@chromium.org

Review URL: https://codereview.chromium.org/271553002

git-svn-id: svn://svn.chromium.org/blink/trunk@173548 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Refactor avoidsFloats() to reflect CSS2.1 spec more clearly

Introduce the 'createsBlockFormatting' concept to RenderBlock::avoidsFloats()
and remove a couple of now-redundant virtualizations of the function.

BUG=

Review URL: https://codereview.chromium.org/268833003

git-svn-id: svn://svn.chromium.org/blink/trunk@173549 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unused RenderLayer accessors

No one calls these functions.

Review URL: https://codereview.chromium.org/267253005

git-svn-id: svn://svn.chromium.org/blink/trunk@173550 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Update Oilpan related comment in GraphicsContext destructor.

I was too fast in concluding that these asserts are not interesting.
There is exactly one case where they do not hold. We should reenable
these asserts for the Oilpan build (but find a different way of
allowing CanvasRenderingContext2D to violate them). For now, updated
comment and filed a bug report to track this.

R=junov@chromium.org
BUG=370793

Review URL: https://codereview.chromium.org/269283006

git-svn-id: svn://svn.chromium.org/blink/trunk@173551 bbb929c8-8fbe-4397-9dbb-9b2b20218538