[iOS][GN] Port ios_web_unittests to build with gn

ios/web/closure_compiler.py

+#!/usr/bin/python
+
+import subprocess
+import sys
+
+def __main__():

[Eugene But (OOO till 7-30), 2015/10/08 16:10:41]

Optional NIT: s/__main__/main ? Otherwise the name is not valid according to
Python Style Guide.

[Eugene But (OOO till 7-30), 2015/10/08 16:10:41]

Need 2 blank lines before top level def

[Dirk Pranke, 2015/10/08 17:49:45]

I wouldn't call this change optional. Please change it :).

Do we really not already have some other script that does this? I would've
thought we had something for android, at least?

[Eugene But (OOO till 7-30), 2015/10/08 18:04:11]

I use gpylint for this.

[Dirk Pranke, 2015/10/08 18:22:29]

I meant, don't we have some other script that calls out to create a jar?

[sdefresne, 2015/10/09 13:54:45]

I've looked around but could find nothing. There is a script
third_party/closure_compiler/compile.py but it adds flags that we do not want on
iOS and we cannot use it directly. Instead I've factored out the code the run
"java_action" and a wrapper python script and moved this to
//build/util/java_action.{gni,py}.

WDYT?

+  return subprocess.check_call(["java", "-jar"] + sys.argv[1:])
+
+if __name__ == "__main__":
+  __main__()