Add mmap and native heap classifiers to memory_inspector.

tools/memory_inspector/memory_inspector/core/exceptions.py

Index: tools/memory_inspector/memory_inspector/core/exceptions.py
diff --git a/tools/memory_inspector/memory_inspector/core/exceptions.py b/tools/memory_inspector/memory_inspector/core/exceptions.py
new file mode 100644
index 0000000000000000000000000000000000000000..a7b2e6d95358af034260ae7c680e0989c409d6b0
--- /dev/null
+++ b/tools/memory_inspector/memory_inspector/core/exceptions.py
@@ -0,0 +1,8 @@
+# Copyright 2014 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.
+
+class MemoryInspectorException(Exception):
+  """Base exception class used for all memory inspector related exceptions."""
+  def __init__(self, value):
+    super(MemoryInspectorException, self).__init__(value)