Fix InlineTextBox::characterWidths() not to measure every substring

Fix InlineTextBox::characterWidths() not to measure every substring

This patch changes InlineTextBox::characterWidths() to use
Font::individualCharacterRanges() rather than to measure every
substring of InlineTextBox. Measuring every substring without context
is very expensive and also is not correct.

When dev tools have long strings without spaces such as minified JS and
accessbility is turned on, the measuring of substrings can almost hang
it up.

Currently, WebAXObject::characterOffsets() is the only user of this
function.

BUG=593679, 568032
TEST=Existing tests cover, such as AutomationApiTest.BoundsForRange

Review URL: https://codereview.chromium.org/1897853004

Cr-Commit-Position: refs/heads/master@{#388162}
(cherry picked from commit 11f1c680cca2250e01121b9bddd7bc6f8fb28a96)

Committed: https://chromium.googlesource.com/chromium/src/+/5b23d300baadb87a84e02b9e22546893858be9c3

[kojii, 2016-04-20 19:11:44]

Description was changed from

==========
Fix InlineTextBox::characterWidths() not to measure every substring

This patch changes InlineTextBox::characterWidths() to use
Font::individualCharacterRanges() rather than to measure every
substring of InlineTextBox. Measuring every substring without context
is very expensive and also is not correct.

When dev tools have long strings without spaces such as minified JS and
accessbility is turned on, the measuring of substrings can almost hang
it up.

Currently, WebAXObject::characterOffsets() is the only user of this
function.

BUG=593679, 568032
TEST=Existing tests cover, such as AutomationApiTest.BoundsForRange

Review URL: https://codereview.chromium.org/1897853004

Cr-Commit-Position: refs/heads/master@{#388162}
(cherry picked from commit 11f1c680cca2250e01121b9bddd7bc6f8fb28a96)
==========

to

==========
Fix InlineTextBox::characterWidths() not to measure every substring

This patch changes InlineTextBox::characterWidths() to use
Font::individualCharacterRanges() rather than to measure every
substring of InlineTextBox. Measuring every substring without context
is very expensive and also is not correct.

When dev tools have long strings without spaces such as minified JS and
accessbility is turned on, the measuring of substrings can almost hang
it up.

Currently, WebAXObject::characterOffsets() is the only user of this
function.

BUG=593679, 568032
TEST=Existing tests cover, such as AutomationApiTest.BoundsForRange

Review URL: https://codereview.chromium.org/1897853004

Cr-Commit-Position: refs/heads/master@{#388162}
(cherry picked from commit 11f1c680cca2250e01121b9bddd7bc6f8fb28a96)

Committed:
https://chromium.googlesource.com/chromium/src/+/5b23d300baadb87a84e02b9e2254...
==========

[kojii, 2016-04-20 19:11:46]

Committed patchset #1 (id:1) manually as
5b23d300baadb87a84e02b9e22546893858be9c3.