Revert of Remove catapult_base from telemetry.

tools/telemetry/catapult_base/refactor/annotated_symbol/reference.py

+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import itertools
+import symbol
+import token
+
+from catapult_base.refactor.annotated_symbol import base_symbol
+from catapult_base.refactor import snippet
+
+
+__all__ = [
+    'Reference',
+]
+
+
+class Reference(base_symbol.AnnotatedSymbol):
+  @classmethod
+  def Annotate(cls, nodes):
+    if not nodes:
+      return None
+    if nodes[0].type != symbol.atom:
+      return None
+    if not nodes[0].children or nodes[0].children[0].type != token.NAME:
+      return None
+
+    for i in xrange(1, len(nodes)):
+      if not nodes:
+        break
+      if nodes[i].type != symbol.trailer:
+        break
+      if len(nodes[i].children) != 2:
+        break
+      if (nodes[i].children[0].type != token.DOT or
+          nodes[i].children[1].type != token.NAME):
+        break
+    else:
+      i = len(nodes)
+
+    return [cls(nodes[:i])] + nodes[i:]
+
+  def __init__(self, children):
+    super(Reference, self).__init__(-1, children)
+
+  @property
+  def type_name(self):
+    return 'attribute_reference'
+
+  @property
+  def value(self):
+    return ''.join(token_snippet.value
+                   for child in self.children
+                   for token_snippet in child.children)
+
+  @value.setter
+  def value(self, value):
+    value_parts = value.split('.')
+
+    # If we have too many children, cut the list down to size.
+    self._children = self._children[:len(value_parts)]
+
+    # Update child nodes.
+    for child, value_part in itertools.izip_longest(
+        self._children, value_parts):
+      if child:
+        # Modify existing children. This helps preserve comments and spaces.
+        child.children[-1].value = value_part
+      else:
+        # Add children as needed.
+        token_snippets = [
+            snippet.TokenSnippet.Create(token.DOT, '.'),
+            snippet.TokenSnippet.Create(token.NAME, value_part),
+        ]
+        self._children.append(snippet.Symbol(symbol.trailer, token_snippets))