Change ShapeResultShaping::computeSpacing to use TextRun::operator[]

Change ShapeResultShaping::computeSpacing to use TextRun::operator[]

ShapeResultShaping::computeSpacing used to use raw pointer to character
buffer in TextRun. This patch changes it to use TextRun::operator[] so
that it can rely on the range-check built into TextRun.

BUG=621843
Review-Url: https://codereview.chromium.org/2090503002
Cr-Commit-Position: refs/heads/master@{#401250}
(cherry picked from commit b18b753c893ad73fea5bd40046b7f55d1247fd10)

Committed: https://chromium.googlesource.com/chromium/src/+/2ed54182b9b0e31c3aab524f7f270f7cdcf2d8a5

[kojii, 2016-07-15 16:15:10]

Description was changed from

==========
Change ShapeResultShaping::computeSpacing to use TextRun::operator[]

ShapeResultShaping::computeSpacing used to use raw pointer to character
buffer in TextRun. This patch changes it to use TextRun::operator[] so
that it can rely on the range-check built into TextRun.

BUG=621843

Review-Url: https://codereview.chromium.org/2090503002
Cr-Commit-Position: refs/heads/master@{#401250}
(cherry picked from commit b18b753c893ad73fea5bd40046b7f55d1247fd10)
==========

to

==========
Change ShapeResultShaping::computeSpacing to use TextRun::operator[]

ShapeResultShaping::computeSpacing used to use raw pointer to character
buffer in TextRun. This patch changes it to use TextRun::operator[] so
that it can rely on the range-check built into TextRun.

BUG=621843

Review-Url: https://codereview.chromium.org/2090503002
Cr-Commit-Position: refs/heads/master@{#401250}
(cherry picked from commit b18b753c893ad73fea5bd40046b7f55d1247fd10)

Committed:
https://chromium.googlesource.com/chromium/src/+/2ed54182b9b0e31c3aab524f7f27...
==========

[kojii, 2016-07-15 16:15:13]

Committed patchset #1 (id:1) manually as
2ed54182b9b0e31c3aab524f7f270f7cdcf2d8a5.