Fixing crash with sig: blink::FrameConsole::addMessage

R=vsevik@chromium.org
BUG=424479

Review URL: https://codereview.chromium.org/644073003

git-svn-id: svn://svn.chromium.org/blink/trunk@184270 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[SVG] DisplayList-based patterns.

Instead of building an ImageBuffer tile (with all the ills of record
time rasterization), build a DisplayList tile and use Skia's
new SkPictureShader mechanism to fill/stroke the shape.

To facilitate this, Pattern is extended to support both bitmap and
picture shaders (the latter only in repeatXY mode -- the only mode
currently used by SVG).

Patterns (and their SkShaders) are cached per RenderSVGResourcePattern
per client. Internally, SkPictureShader also caches its rasterized tile
so there should be no performance degradation.

A handful of tests (about 9) require minor rebaselining (and a couple
have been updated for incorrect patternUnits).

R=pdr@chromium.org,schenney@chromium.org,fs@opera.com,ed@opera.com
BUG=401814,425278

Review URL: https://codereview.chromium.org/453653003

git-svn-id: svn://svn.chromium.org/blink/trunk@184271 bbb929c8-8fbe-4397-9dbb-9b2b20218538