Add a launcher script for the mojo shell on android.

Add a launcher script for the mojo shell on android.

This script will:
- Setup port forwarding.
- Start a local webserver.
- Start the mojo_shell on the android device forwarding its arguments.

R=sky@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/04a2a9caab869347754dc11e142adc60aeaff098

[qsr, 2014-12-12 17:07:02]

qsr@chromium.org changed reviewers:
+ sky@chromium.org

[sky, 2014-12-12 17:54:08]

https://codereview.chromium.org/803573002/diff/20001/mojo/tools/android_mojo_...
File mojo/tools/android_mojo_shell.py (right):

https://codereview.chromium.org/803573002/diff/20001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:18: paths =
Paths(Config(target_os=Config.OS_ANDROID))
Don't you need to support build type, eg debug/release?

https://codereview.chromium.org/803573002/diff/20001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:75: url = None
One problem I have with this is that it isn't readily obvious what the arguments
are, and since we allow launching with nothing there isn't a convenient way to
get a help string. Having to look to source to figure it out isn't very
friendly.

As no url and no arguments isn't particularly compelling, WDYT of having no
arguments print a usage string and exit. To support the no url no args case
require an explicit switch, eg --no-url?

[qsr, 2014-12-15 14:11:22]

https://codereview.chromium.org/803573002/diff/20001/mojo/tools/android_mojo_...
File mojo/tools/android_mojo_shell.py (right):

https://codereview.chromium.org/803573002/diff/20001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:75: url = None
On 2014/12/12 17:54:07, sky wrote:
> One problem I have with this is that it isn't readily obvious what the
arguments
> are, and since we allow launching with nothing there isn't a convenient way to
> get a help string. Having to look to source to figure it out isn't very
> friendly.
> 
> As no url and no arguments isn't particularly compelling, WDYT of having no
> arguments print a usage string and exit. To support the no url no args case
> require an explicit switch, eg --no-url?

 The main reason I didn't do anything like this is because the arguments are the
one for the shell, and I'm pretty sure than any help string won't be updated
when the shell arguments change.

 But that also prevented me to pass the debug/release argument, so I guess this
is incorrect. Updated, to add this argument, a hardcoded help message and still
passing all arguments to the shell. Let me know what you think.

[sky, 2014-12-15 17:13:31]

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
File mojo/tools/android_mojo_shell.py (right):

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:33: "[--args-for=<mojo-app>] "
You don't have --debug/--release here.

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:34: "[--content-handlers=<handlers>] "
Many of the arguments you have here aren't handled. Is that expected?

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:44: <url-lib-path> is searched for shared
libraries named by mojo URLs.
This comment is out of date.

[qsr, 2014-12-15 17:20:13]

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
File mojo/tools/android_mojo_shell.py (right):

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:33: "[--args-for=<mojo-app>] "
On 2014/12/15 17:13:31, sky wrote:
> You don't have --debug/--release here.

 The one this script handled will be handled by arparse itself. Here is the
output:

./mojo/tools/android_mojo_shell.py --help
usage: android_mojo_shell.py [--args-for=<mojo-app>]
[--content-handlers=<handlers>] [--enable-external-applications]
[--disable-cache] [--enable-multiprocess] [--url-mappings=from1=to1,from2=to2]
[<mojo-app> | --no-url] 

A <mojo-app> is a Mojo URL or a Mojo URL and arguments within quotes.
Example: mojo_shell "mojo:js_standalone test.js".
<url-lib-path> is searched for shared libraries named by mojo URLs.
The value of <handlers> is a comma separated list like:
text/html,mojo:html_viewer,application/javascript,mojo:js_content_handler

optional arguments:
  -h, --help  show this help message and exit
  --debug     Debug build (default)
  --release   Release build
  --no-url    Allows not to provide a application URL

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:34: "[--content-handlers=<handlers>] "
On 2014/12/15 17:13:31, sky wrote:
> Many of the arguments you have here aren't handled. Is that expected?

 Yes, all the option that I pass to the shell are not handled. I used
parse_known_args which also return all the arguments that argparse doesn't know
about, and I just pass those to the shell.

https://codereview.chromium.org/803573002/diff/60001/mojo/tools/android_mojo_...
mojo/tools/android_mojo_shell.py:44: <url-lib-path> is searched for shared
libraries named by mojo URLs.
On 2014/12/15 17:13:31, sky wrote:
> This comment is out of date.

 This comment is the one for mojo_shell --help. Not sure we want to update it
only there, so I can make a follow up CL to fix this if you want.

[sky, 2014-12-15 17:52:55]

Ok, LGTM

[qsr, 2014-12-16 09:31:24]

Committed patchset #4 (id:60001) manually as
04a2a9caab869347754dc11e142adc60aeaff098 (presubmit successful).