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=

Review URL: https://chromiumcodereview.appspot.com/22837004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@217405 0039d316-1c4b-4281-b951-d872f2087c98

presubmit_canned_checks.py

@@ -228,7 +228,7 @@ def CheckChangeHasNoCrAndHasOnlyOneEol(input_api, output_api,
 
 def _ReportErrorFileAndLine(filename, line_num, dummy_line):
   """Default error formatter for _FindNewViolationsOfRule."""
-  return '%s, line %s' % (filename, line_num)
+  return '%s:%s' % (filename, line_num)
 
 
 def _FindNewViolationsOfRule(callable_rule, input_api, source_file_filter=None,

tests/presubmit_unittest.py

@@ -2053,7 +2053,7 @@ class CannedChecksUnittest(PresubmitTestsBase):
     self.assertEquals(results1[0].__class__,
         presubmit.OutputApi.PresubmitPromptWarning)
     self.assertEquals(results1[0]._long_text,
-        'makefile.foo, line 46')
+        'makefile.foo:46')
 
   def testCannedCheckLongLines(self):
     check = lambda x, y, z: presubmit_canned_checks.CheckLongLines(x, y, 10, z)