Remove isolatesBlending from render tree dumps

Remove isolatesBlending from render tree dumps

This CL removes the "isolatesBlending" string from render tree dumps. When we
compute render tree dumps, this state is not always up-to-date, which means
we're getting stale information in the render tree dumps. We don't include
other descendant-dependent flags in render tree dumps for this reason.

This CL costs us some test coverage, but the appropriate way to regain that
test coverage to use reference tests to ensure that the pixels we draw are
correctly blended rather than hard-coding internal state from the engine into
test results.

R=esprehn@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180111

[esprehn, 2014-08-12 22:13:17]

Why not do a compositing update before doing a render tree dump?

lgtm

[esprehn, 2014-08-12 22:13:35]

Land it!

[abarth-chromium, 2014-08-12 22:45:38]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-08-12 22:47:03]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/abarth@chromium.org/466943002/1

[commit-bot: I haz the power, 2014-08-12 22:53:07]

Change committed as 180111