Implement hyphenation for DumpRenderTree.

Implement hyphenation for DumpRenderTree.
This change implements the platform functions added by my WebKit change r124434 <http://trac.webkit.org/changeset/124434>; for DumpRenderTree. It is a simplified version of my r146964 <http://crrev.com/146964>;.

BUG=47083
TEST=hyphen*.html
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=160337

[Hironori Bono, 2012-10-02 09:13:47]

Greetings Tony,

Thank you for your review in advance. As listed in the trybot results, this
change needs another WebKit change that rebaselines layout-test results which
use hyphenation. Is it possible to land this change and update test results, or
should I update test results and land this change?

Regards,

Hironori Bono

[tony, 2012-10-02 18:18:02]

LGTM.

FOr the layout tests, I would,
1) Mark the layout tests as as failing in
webkit/tools/layout_tests/test_expectations.txt (I would just do it in this
change).
2) Roll the chromium revision in WebKit/Source/WebKit/chromium/DEPS to include
this change.
3) Rebaseline the tests.
4) After the WebKit DEPS in chromium are updated to include the baselines,
delete the changes to test_expectations.txt.

[commit-bot: I haz the power, 2012-10-03 09:05:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hbono@chromium.org/11014014/17003

[commit-bot: I haz the power, 2012-10-04 01:51:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hbono@chromium.org/11014014/17003

[commit-bot: I haz the power, 2012-10-04 01:53:05]

Change committed as 160044

[Nico, 2013-01-20 04:45:11]

https://chromiumcodereview.appspot.com/11014014/diff/6004/webkit/support/test...
File webkit/support/test_webkit_platform_support.cc (right):

https://chromiumcodereview.appspot.com/11014014/diff/6004/webkit/support/test...
webkit/support/test_webkit_platform_support.cc:518: if
(!PathService::Get(base::DIR_SOURCE_ROOT, &path))
This is possibly not correct on linux for standalone webkit builds, see
https://code.google.com/p/chromium/issues/detail?id=171146

https://chromiumcodereview.appspot.com/11014014/diff/6004/webkit/support/test...
webkit/support/test_webkit_platform_support.cc:524: if
(!file_util::ReadFileToString(path, &dictionary))
Relatedly, should this be DCHECK()ed?