Move code starting the editor into a common function.

tests/gclient_utils_test.py

Index: tests/gclient_utils_test.py
diff --git a/tests/gclient_utils_test.py b/tests/gclient_utils_test.py
index ea4f50256138163772fc9068e8bf27d166ea3dc9..3e24c01b15d4dcdf1175d1f51e6bb7124c262484 100755
--- a/tests/gclient_utils_test.py
+++ b/tests/gclient_utils_test.py
@@ -31,12 +31,13 @@ class GclientUtilsUnittest(GclientUtilBase):
         'Annotated', 'AutoFlush', 'CheckCallAndFilter',
         'CheckCallAndFilterAndHeader', 'Error', 'ExecutionQueue', 'FileRead',
         'FileWrite', 'FindFileUpwards', 'FindGclientRoot',
-        'GetGClientRootAndEntries', 'IsDateRevision', 'MakeDateRevision',
-        'MakeFileAutoFlush', 'MakeFileAnnotated', 'PathDifference',
-        'PrintableObject', 'RemoveDirectory', 'SplitUrlRevision',
-        'SyntaxErrorToError', 'Wrapper', 'WorkItem',
+        'GetGClientRootAndEntries', 'GetEditor', 'IsDateRevision',
+        'MakeDateRevision', 'MakeFileAutoFlush', 'MakeFileAnnotated',
+        'PathDifference', 'PrintableObject', 'RemoveDirectory', 'RunEditor',
+        'SplitUrlRevision', 'SyntaxErrorToError', 'Wrapper', 'WorkItem',
         'errno', 'lockedmethod', 'logging', 'os', 'Queue', 're', 'rmtree',
-        'safe_makedirs', 'stat', 'subprocess2', 'sys','threading', 'time',
+        'safe_makedirs', 'stat', 'subprocess2', 'sys', 'tempfile', 'threading',
+        'time',
     ]
     # If this test fails, you should add the relevant test.
     self.compareMembers(gclient_utils, members)