Modify ui::ElideRectangleText() to honor trailing newlines.

Modify ui::ElideRectangleText() to honor trailing newlines.

Trailing whitespace without a \n character is still trimmed away.
Adds additional tests for this.

Also, makes the code use ContainsOnlyWhitespace() from base
and makes the implementation of ContainsOnlyWhitespace()
shorter (based on the code that was in text_elider.cc.)

BUG=126297
TEST=New tests in text_elider_unittest.cc

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=137061

[sky, 2012-05-11 17:32:14]

LGTM

[Alexei Svitkine (slow), 2012-05-11 17:36:55]

+brettw for base/ ownership

[brettw, 2012-05-11 21:36:20]

base LGTM

[commit-bot: I haz the power, 2012-05-15 00:26:29]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/asvitkine@chromium.org/10386016/12002

[commit-bot: I haz the power, 2012-05-15 02:43:12]

Change committed as 137061

[tfarina, 2012-05-15 02:49:52]

https://chromiumcodereview.appspot.com/10386016/diff/12002/base/string_util.cc
File base/string_util.cc (right):

https://chromiumcodereview.appspot.com/10386016/diff/12002/base/string_util.c...
base/string_util.cc:381: for (std::string::const_iterator i(str.begin()); i !=
str.end(); ++i) {
Can we simplify this as well?

[Alexei Svitkine (slow), 2012-05-15 03:04:22]

https://chromiumcodereview.appspot.com/10386016/diff/12002/base/string_util.cc
File base/string_util.cc (right):

https://chromiumcodereview.appspot.com/10386016/diff/12002/base/string_util.c...
base/string_util.cc:381: for (std::string::const_iterator i(str.begin()); i !=
str.end(); ++i) {
On 2012/05/15 02:49:52, tfarina wrote:
> Can we simplify this as well?

I considered it, but unfortunately kWhitespaceASCII is not the same set as
what's checked by IsAsciiWhitespace() and I didn't want to change any behaviour
here with this cleanup.

(I don't understand the implications of this change to judge whether it would be
correct to make it.)