Android: splits cache_control and perf_control.

build/android/pylib/perf/cache_control.py

Index: build/android/pylib/perf/cache_control.py
diff --git a/build/android/pylib/perf/cache_control.py b/build/android/pylib/perf/cache_control.py
new file mode 100644
index 0000000000000000000000000000000000000000..1b0a4c2b95529fa549b2db7b9ac997861b4c5f05
--- /dev/null
+++ b/build/android/pylib/perf/cache_control.py
@@ -0,0 +1,16 @@
+# Copyright 2013 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 CacheControl(object):
+  _DROP_CACHES = '/proc/sys/vm/drop_caches'
+
+  def __init__(self, adb):
+    self._adb = adb
+
+  def DropRamCaches(self):
+    """Drops the filesystem ram caches for performance testing."""
+    self._adb.RunShellCommandWithSU('sync')
+    self._adb.SetProtectedFileContents(CacheControl._DROP_CACHES, '3')
+