Remove unused function _invert_dictionary from baseline_optimizer.py.

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

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/baseline_optimizer.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/baseline_optimizer.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/baseline_optimizer.py
index ee180014ab16fc3b7bdbf62f6711f0d6cd78a85a..d67aef8de41079102bb0d76cfa4d172de32e78dd 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/baseline_optimizer.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/baseline_optimizer.py
@@ -35,17 +35,6 @@ from webkitpy.common.memoized import memoized
 _log = logging.getLogger(__name__)
 
 
-# FIXME: Should this function be somewhere more general?
-def _invert_dictionary(dictionary):
-    inverted_dictionary = {}
-    for key, value in dictionary.items():
-        if inverted_dictionary.get(value):
-            inverted_dictionary[value].append(key)
-        else:
-            inverted_dictionary[value] = [key]
-    return inverted_dictionary
-
-
 class BaselineOptimizer(object):
     ROOT_LAYOUT_TESTS_DIRECTORY = 'LayoutTests'