-Add README for building go sample application

-Add README for building go sample application
-Add README for building go system bindings test
-Build rule changes

R=jamesr@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/1a2084a2f46271a3b07f6e060d269314cbfd4405

[gauthamt, 2014-10-29 21:36:13]

gautham.dorai@gmail.com changed reviewers:
+ jamesr@chromium.org

[qsr, 2014-10-30 10:43:46]

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

[qsr, 2014-10-30 10:43:47]

https://codereview.chromium.org/647573004/diff/1/mojo/go/sample_app/README.txt
File mojo/go/sample_app/README.txt (right):

https://codereview.chromium.org/647573004/diff/1/mojo/go/sample_app/README.tx...
mojo/go/sample_app/README.txt:12: $
NDK_CC=$NDK_ROOT/bin/arm-linux-androideabi-gcc
Why do you need all of this? If you have an android checkout, this is already in
third-party. Am I missing something?

[gauthamt, 2014-10-30 17:51:22]

https://codereview.chromium.org/647573004/diff/1/mojo/go/sample_app/README.txt
File mojo/go/sample_app/README.txt (right):

https://codereview.chromium.org/647573004/diff/1/mojo/go/sample_app/README.tx...
mojo/go/sample_app/README.txt:12: $
NDK_CC=$NDK_ROOT/bin/arm-linux-androideabi-gcc
On 2014/10/30 10:43:47, qsr wrote:
> Why do you need all of this? If you have an android checkout, this is already
in
> third-party. Am I missing something?

Modified the instructions to just generate the desired toolchain from
third-party. 

I saw that some of the pre-built toolchains dont seem to have all the libraries
(eg: sysroot/,  include/)

[jamesr, 2014-10-30 22:20:44]

build/go is currently being snapshotted from chromium along with the rest of
build/**, so any change you land there will be blown away by the next update. 
Since build/go isn't being used by anything in chromium (it was added just for
mojo) I'd suggest you move these rules to another location in the mojo
repository that isn't under build/ and update it there and delete the copy in
chromium/.  The alternative in order to keep this location in the repo would be
to make the roll script more complicated to preserve build/go/ but that doesn't
seem very appetizing.

[jamesr, 2014-11-04 19:03:11]

Sorry, didn't realize this was still pending. READMEs lgtm

[gautham, 2014-11-04 19:06:54]

Committed patchset #2 (id:20001) manually as
1a2084a2f46271a3b07f6e060d269314cbfd4405 (presubmit successful).