Change default ReportErrorFileAndLine to use filename:lineno format.

Change default ReportErrorFileAndLine to use filename:lineno format.

Currently the output is:

Found line ending with white spaces in:
cc/trees/layer_tree_host_impl_unittest.cc, line 379

This format is extremely annoying because you must combine the
file and line number together by hand. A more standard format
for expressing a position in a file is filename:lineno. This
changes the format to match:

Found line ending with white spaces in:
cc/trees/layer_tree_host_impl_unittest.cc:379

R=maruel@chromium.org
BUG=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=217405

[M-A Ruel, 2013-08-14 00:25:35]

lgtm

[commit-bot: I haz the power, 2013-08-14 00:25:44]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/danakj@chromium.org/22837004/5001

[commit-bot: I haz the power, 2013-08-14 00:27:26]

Change committed as 217405