Rebaseline canvas2d-api-changes.html

The newly added API methods need to be investigated.

BUG=
TBR=aandrey

Review URL: https://codereview.chromium.org/332343009

git-svn-id: svn://svn.chromium.org/blink/trunk@177229 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add per-fragment early-out for getCharNumAtPosition

Since this is a spatial query, and a SVGTextFragment already contain an
approximation of it's own bounds, we can use those to perform a reasonably
efficient early-rejection test.
As an example: A TC using the textPath-data from issue 267504 [1] and a
mouse-move handler that uses getCharNumAtPosition to check which
"character" (glyph) is under the pointer consumes 0.005-0.2ms, compared to
0.2-0.5ms without this patch (before the CL in [2], this was 5-10ms!).
The TC mentioned in [2] now also weighs in at a few thousand us at worst.

[1] http://jsbin.com/imajow/1/quiet
[2] https://codereview.chromium.org/353003002

Review URL: https://codereview.chromium.org/355173002

git-svn-id: svn://svn.chromium.org/blink/trunk@177230 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Simplify SVGTextQuery::modifyStartEndPositionsRespectingLigatures

Simplify this method by passing it the fragment in question, and then use
SVGTextFragment::metricsListOffset to get a reasonable starting point.
Rewrite the big loop into two simpler loops - one for each end-point.
This shaves another ~15% off the TC in the bug (on top of [1]).

[1] https://codereview.chromium.org/359783002/

BUG=267504

Review URL: https://codereview.chromium.org/355373003

git-svn-id: svn://svn.chromium.org/blink/trunk@177231 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move HTMLTagCollection to its own file

Move HTMLTagCollection to its own file for clarity, instead of having it
in TagCollection.h. There is no functional change in this CL.

R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/355163004

git-svn-id: svn://svn.chromium.org/blink/trunk@177232 bbb929c8-8fbe-4397-9dbb-9b2b20218538