[android] Add support for providing flags to instrumentation tests directly.

build/android/test_runner.py

Index: build/android/test_runner.py
diff --git a/build/android/test_runner.py b/build/android/test_runner.py
index 99711722442a312ce6ce0a519f62a3275c0f5bf1..c97617895865821aa66db60627a3e52cfcbc6509 100755
--- a/build/android/test_runner.py
+++ b/build/android/test_runner.py
@@ -366,10 +366,11 @@ def AddInstrumentationTestOptions(parser):
   group.add_argument('--coverage-dir', type=os.path.realpath,
                      help=('Directory in which to place all generated '
                            'EMMA coverage files.'))
-  group.add_argument('--device-flags', dest='device_flags',
+  group.add_argument('--device-flags',
+                     '--test-arguments',

[mikecase (-- gone --), 2017/03/10 18:08:03]

Why are we adding another alias for this?

also, --command-line-flags seems like a better name for this arg over
--device-flags and --test-arguments.

[jbudorick, 2017/03/10 18:11:17]

--test-arguments is what it is for gtests, hence the alias. I suppose
--command-line-flags/--command-line-flags-file would be a more sensible end
state, though.

[jam, 2017/03/10 19:20:58]

As a non-Android developer, having to specify command lines differently is
confusing.

[jbudorick, 2017/03/10 19:38:44]

hmm, we might be able to pass arguments that the test runner doesn't recognize
on to the device, though I'd consider that change to be a bit more risky. It'd
conceivably let you do

  "args": [
    "--enable-browser-side-navigation",
  ],

in the JSON.

+                     dest='device_flags',
                      type=os.path.realpath,
-                     help='The relative filepath to a file containing '
-                          'command-line flags to set on the device')
+                     help='Command-line flags to set on the device')

[shenghuazhang, 2017/03/10 19:04:57]

Since this is matching the argument in gtest, and the help comment for gtest is:
    help='Additional arguments to pass to the test.'

which is different with it. Wonder if it can be unified s.t. knowing the support
has the same meaning as gtest explicitly.

   group.add_argument('--device-flags-file', type=os.path.realpath,
                      help='The relative filepath to a file containing '
                           'command-line flags to set on the device')