Refactor print-layout-test-times and add unit tests.

Tools/Scripts/webkitpy/common/system/systemhost.py

Index: Tools/Scripts/webkitpy/common/system/systemhost.py
diff --git a/Tools/Scripts/webkitpy/common/system/systemhost.py b/Tools/Scripts/webkitpy/common/system/systemhost.py
index 3b4439ee4785bdc220ee72333179268499ad12a3..52b88d6fcc1d525a4ac3586c4a0e186a9942bd2a 100644
--- a/Tools/Scripts/webkitpy/common/system/systemhost.py
+++ b/Tools/Scripts/webkitpy/common/system/systemhost.py
@@ -43,3 +43,12 @@ class SystemHost(object):
 
     def copy_current_environment(self):
         return environment.Environment(os.environ.copy())
+
+    def print_(self, *args, **kwargs):

[Dirk Pranke, 2013/09/19 23:50:56]

Adding this wrapper allows us to capture stdout and stderr output w/o needing
the full hoop-jumping of outputcapture (and needing to step on and restore
sys.stdout and sys.stderr).

Also, if we change code to call host.print_() rather than "print", this gives us
a simpler migration path to Python3 (where print becomes a function, not a
statement).

Unfortunately "print" is a reserved word and so we can't call the method
"print". Using "print_" follows the convention in the popular 2to3 wrapper
library, 6.

+        sep = kwargs.get('sep', ' ')
+        end = kwargs.get('end', '\n')
+        file = kwargs.get('file', None)
+        stderr = kwargs.get('stderr', False)
+
+        file = file or (sys.stderr if stderr else sys.stdout)
+        file.write(sep.join([str(arg) for arg in args]) + end)