[Android] Split out the instrumentation test runner, sharder, and dispatcher.

build/android/pylib/instrumentation/test_sharder.py

+# Copyright (c) 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.
+
+"""Sharder for the instrumentation tests."""
+
+from pylib.base import base_test_sharder
+from pylib.base import sharded_tests_queue
+
+import test_runner
+
+
+class TestSharder(base_test_sharder.BaseTestSharder):
+  """Responsible for sharding the tests on the connected devices."""
+
+  def __init__(self, attached_devices, options, tests, apks):
+    super(TestSharder, self).__init__(attached_devices,
+                                      options.build_type)
+    self.options = options
+    self.tests = tests
+    self.apks = apks
+
+  def SetupSharding(self, tests):
+    """Called before starting the shards."""
+    base_test_sharder.SetTestsContainer(sharded_tests_queue.ShardedTestsQueue(
+        len(self.attached_devices), tests))
+
+  def CreateShardedTestRunner(self, device, index):
+    """Creates a sharded test runner.
+
+    Args:
+      device: Device serial where this shard will run.
+      index: Index of this device in the pool.
+
+    Returns:
+      A TestRunner object.
+    """
+    return test_runner.TestRunner(self.options, device, None, False, index,
+                                  self.apks, [])