Bug fix: toPositionInCoposedTree should treat positions with insertion points

Bug fix: toPositionInCoposedTree should treat positions with insertion points

Now a position is passed to toPositionInCoposedTree and its related node
is an insertion point like <content>, this conversion hits an assertion
because there should not be any insertion points in the composed tree
world. This CL fixes this to avoid to use the insertion point in such
case.

BUG=504035
TEST=webkit_unit_tests --gtest_filter=PositionTest.*

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197804

[hajimehoshi, 2015-06-25 05:50:22]

hajimehoshi@chromium.org changed reviewers:
+ tkent@chromium.org

[hajimehoshi, 2015-06-25 05:50:22]

PTAL

[tkent, 2015-06-25 06:00:49]

lgtm

[hajimehoshi, 2015-06-25 06:03:32]

The CQ bit was checked by hajimehoshi@chromium.org

[commit-bot: I haz the power, 2015-06-25 09:01:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1205023003/1

[commit-bot: I haz the power, 2015-06-25 09:08:03]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197804