Fix pylint warnings in webkitpy/common/.

third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/scm.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/scm.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/scm.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/scm.py
index 4778916e01ac62122bbcfff835e15ecfad6740e3..b64ee86cd8a58ad0593075c6d21b6cfd96642616 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/scm.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/scm.py
@@ -34,14 +34,13 @@ import re
 import sys
 
 from webkitpy.common.system.executive import Executive
-from webkitpy.common.system.executive import ScriptError
 from webkitpy.common.system.filesystem import FileSystem
 
 _log = logging.getLogger(__name__)
 
 
 # SCM methods are expected to return paths relative to self.checkout_root.
-class SCM:
+class SCM(object):
 
     def __init__(self, cwd, executive=None, filesystem=None):
         self.cwd = cwd
@@ -50,11 +49,12 @@ class SCM:
         self.checkout_root = self.find_checkout_root(self.cwd)
 
     # A wrapper used by subclasses to create processes.
-    def _run(self, args, cwd=None, input=None, error_handler=None, return_exit_code=False, return_stderr=True, decode_output=True):
+    def _run(self, args, cwd=None, input_func=None, error_handler=None,
+             return_exit_code=False, return_stderr=True, decode_output=True):
         # FIXME: We should set cwd appropriately.
         return self._executive.run_command(args,
                                            cwd=cwd,
-                                           input=input,
+                                           input_func=input_func,
                                            error_handler=error_handler,
                                            return_exit_code=return_exit_code,
                                            return_stderr=return_stderr,
@@ -81,6 +81,10 @@ class SCM:
     def _subclass_must_implement():
         raise NotImplementedError("subclasses must implement")
 
+    # Most methods here are abstract methods which don't use their arguments.
+    # FIXME: Merge Git and SCM and remove the abstract base methods.
+    # pylint: disable=unused-argument
+
     @classmethod
     def in_working_directory(cls, path, executive=None):
         SCM._subclass_must_implement()