Add tools/perf essential Python files.

tools/perf/core/__init__.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.

tools/perf/core/path_util.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 contextlib
+import os
+import sys
+
+
+@contextlib.contextmanager
+def SysPath(path, position=None):
+    if position is None:
+        sys.path.append(path)
+    else:
+        sys.path.insert(position, path)
+    try:
+        yield
+    finally:
+        if sys.path[-1] == path:
+            sys.path.pop()
+        else:
+            sys.path.remove(path)
+
+
+def GetChromiumSrcDir():
+    return os.path.abspath(os.path.join(os.path.dirname(__file__), '..', '..', '..'))
+
+
+def GetTelemetryDir():
+    return os.path.join(GetChromiumSrcDir(), 'third_party', 'catapult', 'telemetry')
+
+
+def GetTracingDir():
+    return os.path.join(GetChromiumSrcDir(), 'third_party', 'catapult', 'tracing')
+
+
+def GetPyUtilsDir():
+    return os.path.join(GetChromiumSrcDir(), 'third_party', 'catapult', 'common', 'py_utils')
+
+
+def GetPerfDir():
+    return os.path.join(GetChromiumSrcDir(), 'tools', 'perf')
+
+
+def GetPerfStorySetsDir():
+    return os.path.join(GetPerfDir(), 'page_sets')
+
+
+def GetOfficialBenchmarksDir():
+    return os.path.join(GetPerfDir(), 'benchmarks')
+
+
+def GetContribDir():
+    return os.path.join(GetPerfDir(), 'contrib')
+
+
+def GetAndroidPylibDir():
+    return os.path.join(GetChromiumSrcDir(), 'build', 'android')
+
+
+def GetVariationsDir():
+    return os.path.join(GetChromiumSrcDir(), 'tools', 'variations')
+
+
+def AddTelemetryToPath():
+    telemetry_path = GetTelemetryDir()
+    if telemetry_path not in sys.path:
+        sys.path.insert(1, telemetry_path)
+
+
+def AddTracingToPath():
+    tracing_path = GetTracingDir()
+    if tracing_path not in sys.path:
+        sys.path.insert(1, tracing_path)
+
+
+def AddPyUtilsToPath():
+    py_utils_dir = GetPyUtilsDir()
+    if py_utils_dir not in sys.path:
+        sys.path.insert(1, py_utils_dir)
+
+
+def AddAndroidPylibToPath():
+    android_pylib_path = GetAndroidPylibDir()
+    if android_pylib_path not in sys.path:
+        sys.path.insert(1, android_pylib_path)
+
+
+def GetExpectationsPath():
+    return os.path.join(GetPerfDir(), 'expectations.config')