Refactor away SVGTextMetricsBuilder::advance

Refactor away SVGTextMetricsBuilder::advance

This method has two logical parts: Advancing the text position and
checking for termination, and computing the metrics for the current
character.
Split this method to better show this. The latter part is put into a
new method, computeMetricsForCurrentCharacter, while the former part is
open-coded in SVGTextMetricsBuilder::measureTextRenderer.
The advance{Simple,Complex}Text methods are renamed to
computeMetricsForCurrentCharacter{Simple,Complex}.

With this change, it becomes easier to see that
SVGTextMetricsBuilder::m_currentMetrics can be trivially removed in favor
of returning it from computeMetricsForCurrentCharacter, and storing it on
the stack in SVGTextMetricsBuilder::measureTextRenderer.
The same is true for SVGTextMetricsBuilder::m_complexStartToCurrentMetrics,
which can be made local to computeMetricsForCurrentCharacterComplex.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168461

[Stephen Chennney, 2014-03-04 16:57:31]

LGTM. It's great that you're in this area.

[fs, 2014-03-04 17:26:44]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2014-03-04 17:27:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/fs@opera.com/184103024/1

[commit-bot: I haz the power, 2014-03-05 10:17:01]

Change committed as 168461