Use common stack trace code in Android port

Use common stack trace code in Android port

StackTrace has a common implementation (stack_trace.cc) as well as
platform specific ones (e.g, stack_strace_android.cc). This change makes
the Android port also use the common part instead of duplicating it.

This also fixes a Clang compilation failure due to the unused private
member variables.

Change-Id: I6ebb4815097b587cb4c6c639e5893f7759a3ff79
Reviewed-on: https://gerrit-int.chromium.org/21399
Reviewed-by: Marcus Bulach <bulach@google.com>;
Tested-by: Sami Kyostila <skyostil@google.com>;

BUG=
TEST=Build with clang and -Wunused-private-field


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=147424

[willchan no longer on Chromium, 2012-07-18 19:25:22]

lgtm

[commit-bot: I haz the power, 2012-07-19 09:13:49]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/skyostil@chromium.org/10702142/1

[commit-bot: I haz the power, 2012-07-19 10:49:20]

Change committed as 147424