Push uiautomator test jar to its own folder in tmp

When running uiautomator tests through test_runner the contents of
/data/local/tmp is hashed using md5sum_bin to see if a push is needed. This is
inefficient when tmp contains unrelated large files, and it relies on md5sum.cc
to be able to handle a wide range of filetypes including named pipes.

By transferring chrome_shell_uiautomator.dex.jar to /data/local/tmp/uiautomator
we hash fewer files, and can be confident that the files are only files we care
about (of type .jar or .dex.jar).

Tested on a Nexus:
./build/android/test_runner.py uiautomator -v -v
  --test-jar=chrome_shell_uiautomator_tests --package=chrome_shell

BUG=432341

Review URL: https://codereview.chromium.org/715153002

Cr-Commit-Position: refs/heads/master@{#303872}

AUTHORS

@@ -110,6 +110,7 @@ Darshini KN <kn.darshini@samsung.com>
 David Benjamin <davidben@mit.edu>
 David Erceg <erceg.david@gmail.com>
 David Futcher <david.mike.futcher@gmail.com>
+David Leen <davileen@amazon.com>
 David McAllister <mcdavid@amazon.com>
 Deepak Dilip Borade <deepak.db@samsung.com>
 Deepak Mittal <deepak.m1@samsung.com>

build/android/pylib/uiautomator/test_package.py

@@ -11,6 +11,11 @@ from pylib.instrumentation import test_jar
 
 
 class TestPackage(test_jar.TestJar):
+
+  UIAUTOMATOR_PATH = 'uiautomator/'
+  UIAUTOMATOR_DEVICE_DIR = os.path.join(constants.TEST_EXECUTABLE_DIR,
+                                        UIAUTOMATOR_PATH)
+
   def __init__(self, jar_path, jar_info_path):
     test_jar.TestJar.__init__(self, jar_info_path)
 
@@ -24,4 +29,5 @@ class TestPackage(test_jar.TestJar):
 
   # Override.
   def Install(self, device):
-    device.PushChangedFiles([(self._jar_path, constants.TEST_EXECUTABLE_DIR)])
+    device.PushChangedFiles([(self._jar_path, self.UIAUTOMATOR_DEVICE_DIR +
+                              self.GetPackageName())])

build/android/pylib/uiautomator/test_runner.py

@@ -73,7 +73,8 @@ class TestRunner(instr_test_runner.TestRunner):
                       package=self._package),
         blocking=True,
         force_stop=True)
-    cmd = ['uiautomator', 'runtest', self.test_pkg.GetPackageName(),
+    cmd = ['uiautomator', 'runtest',
+           self.test_pkg.UIAUTOMATOR_PATH + self.test_pkg.GetPackageName(),
            '-e', 'class', test]
     return self.device.RunShellCommand(cmd, timeout=timeout, retries=0)