Adds --skip-clear-data flag to android's test_runner.py

build/android/pylib/local/device/local_device_gtest_run.py

 # 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.
 
 import imp
 import itertools
 import os
 import posixpath
 
 from devil.android import device_errors
@@ skipping 326 matching lines @@
     timeout = (self._test_instance.shard_timeout
                * self.GetTool(device).GetTimeoutScale())
     output = self._delegate.Run(
         test, device, flags=self._test_instance.test_arguments,
         timeout=timeout, retries=0)
     for s in self._servers[str(device)]:
       s.Reset()
     if self._test_instance.app_files:
       self._delegate.PullAppFiles(device, self._test_instance.app_files,
                                   self._test_instance.app_file_dir)
-    # Clearing data when using incremental install wipes out cached optimized
-    # dex files (and shouldn't be necessary by tests anyways).
-    if not self._env.incremental_install:
+    if not self._test_instance.skip_clear_data:

[jbudorick, 2016/02/03 14:38:27]

Why are we adding this in addition to --incremental-install?

[agrieve, 2016/02/03 16:34:32]

I'm envisioning adding a --fast-local-dev (or better name appreciated), which
will turn on all of these iffy flags, and which will be used by the _incremental
generated script, but also useful for non-incremental local builds.

       self._delegate.Clear(device)
 
     # Parse the output.
     # TODO(jbudorick): Transition test scripts away from parsing stdout.
     results = self._test_instance.ParseGTestOutput(output)
     return results
 
   #override
   def TearDown(self):
     @local_device_test_run.handle_shard_failures
     def individual_device_tear_down(dev):
       for s in self._servers.get(str(dev), []):
         s.TearDown()
 
       tool = self.GetTool(dev)
       tool.CleanUpEnvironment()
 
     self._env.parallel_devices.pMap(individual_device_tear_down)