Empty webkitpy/tool/steps/__init__.py; update imports.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/prettydiff.py

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 from webkitpy.tool.commands.abstractsequencedcommand import AbstractSequencedCommand
-from webkitpy.tool import steps
+from webkitpy.tool.steps.confirmdiff import ConfirmDiff
 
 
 class PrettyDiff(AbstractSequencedCommand):
     name = "pretty-diff"
     help_text = "Shows the pretty diff in the default browser"
     show_in_main_help = True
     steps = [
-        steps.ConfirmDiff,
+        ConfirmDiff,
     ]