Actually make use of the may_prompt flag.

This is annoying when using gcl presubmit.

TEST=unit test
BUG=none
Review URL: http://codereview.chromium.org/122010

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@18141 0039d316-1c4b-4281-b951-d872f2087c98

presubmit_support.py

@@ -767,7 +767,7 @@ def DoPresubmitChecks(change_info,
                             may_prompt=False):
           error_count += 1
         output_stream.write('\n')
-  if not errors and warnings:
+  if not errors and warnings and may_prompt:
     output_stream.write(
       'There were presubmit warnings. Sure you want to continue? (y/N): ')
     response = input_stream.readline()

tests/presubmit_unittest.py

@@ -380,7 +380,7 @@ class PresubmitUnittest(PresubmitTestsBase):
     output = StringIO.StringIO()
     input = StringIO.StringIO('n\n')  # say no to the warning
     self.failIf(presubmit.DoPresubmitChecks(ci, False, True, output, input,
-                                            None, False))
+                                            None, True))
     self.assertEqual(output.getvalue().count('??'), 2)
 
     output = StringIO.StringIO()
@@ -391,7 +391,7 @@ class PresubmitUnittest(PresubmitTestsBase):
                                                 output,
                                                 input,
                                                 None,
-                                                False))
+                                                True))
     self.assertEquals(output.getvalue().count('??'), 2)
 
   def testDoPresubmitChecksNoWarningPromptIfErrors(self):