android: Don't use cpp to strip comments in jni_generator.

For the WebView build, invoking "cpp" from $PATH is problematic on some
host platforms because the Android build system is intended to use
hermetic toolchains. However, using the hermetic toolchain correctly is
also difficult.
    
To avoid this, use a regex to strip comments instead of invoking cpp.
This regex shoud handle all the Java source cases correctly (it deals
with strings that contain //, /* or */) and should also improve
performance compared to invoking cpp. The JNI generator tests pass with
this change.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=263650

[Torne, 2014-04-11 13:21:49]

Argh, none of this works on the bots even though it works on my machine for
gross reasons. I'll have another go in a bit, you can ignore this for now :)

[Torne, 2014-04-11 14:59:55]

OK, I've completely rewritten this CL to just drop the use of cpp entirely, and
instead just strip comments with a regex (which is what the script used to do
before the use of cpp was introduced). However, this regex should actually
handle all the cases including comment delimiters nested inside strings, and so
this should be okay to use (and also faster than shelling out to cpp).

[bulach, 2014-04-14 11:30:44]

lgtm, thanks! small suggestions..

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
File base/android/jni_generator/jni_generator.py (right):

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
base/android/jni_generator/jni_generator.py:600: _comment_remover_regex =
re.compile(
nit: maybe move this before __init__ ? it took me a couple of seconds to
understand the scope :)

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
base/android/jni_generator/jni_generator.py:604: def _RemoveComments(self,
contents):
...and then perhaps make this @staticmethod?

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
base/android/jni_generator/jni_generator.py:616: return ""
nit: s/""/''/

[Torne, 2014-04-14 11:41:05]

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
File base/android/jni_generator/jni_generator.py (right):

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
base/android/jni_generator/jni_generator.py:600: _comment_remover_regex =
re.compile(
On 2014/04/14 11:30:44, bulach wrote:
> nit: maybe move this before __init__ ? it took me a couple of seconds to
> understand the scope :)

Done.

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
base/android/jni_generator/jni_generator.py:604: def _RemoveComments(self,
contents):
On 2014/04/14 11:30:44, bulach wrote:
> ...and then perhaps make this @staticmethod?

Static methods can't access members of the class, but I can make it a class
method.

https://codereview.chromium.org/227303003/diff/60001/base/android/jni_generat...
base/android/jni_generator/jni_generator.py:616: return ""
On 2014/04/14 11:30:44, bulach wrote:
> nit: s/""/''/

Done.

[Torne, 2014-04-14 14:13:18]

The CQ bit was checked by torne@chromium.org

[commit-bot: I haz the power, 2014-04-14 14:13:32]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/torne@chromium.org/227303003/80001

[commit-bot: I haz the power, 2014-04-14 17:30:13]

Change committed as 263650