GN: Add default target

GN: Add default target

This reduces the number of objects when not specifying a
build target during compile. This is especially significant for Android
where the number of objects decreases from 3322 to 1761.

BUG=libyuv:644
R=fbarchard@google.com

Committed: https://chromium.googlesource.com/libyuv/libyuv/+/1cd384140daa0f30a3df5170903018a761028397

[kjellander_chromium, 2016-10-05 07:46:59]

Description was changed from

==========
GN: Add default target

This reduces the number of objects when not specifying a
build target during compile. This is especially significant for Android
where the number of objects becomes instead of .X

BUG=libyuv:644
==========

to

==========
GN: Add default target

This reduces the number of objects when not specifying a
build target during compile. This is especially significant for Android
where the number of objects decreases from 3322 to 1761.

BUG=libyuv:644
==========

[kjellander_chromium, 2016-10-05 07:46:59]

kjellander@chromium.org changed reviewers:
+ fbarchard@chromium.org

[fbarchard1, 2016-10-05 18:15:19]

fbarchard@google.com changed reviewers:
+ fbarchard@google.com

[fbarchard1, 2016-10-05 18:15:19]

lgtm

[fbarchard1, 2016-10-05 18:17:30]

Description was changed from

==========
GN: Add default target

This reduces the number of objects when not specifying a
build target during compile. This is especially significant for Android
where the number of objects decreases from 3322 to 1761.

BUG=libyuv:644
==========

to

==========
GN: Add default target

This reduces the number of objects when not specifying a
build target during compile. This is especially significant for Android
where the number of objects decreases from 3322 to 1761.

BUG=libyuv:644
R=fbarchard@google.com

Committed:
https://chromium.googlesource.com/libyuv/libyuv/+/1cd384140daa0f30a3df5170903...
==========

[fbarchard1, 2016-10-05 18:17:32]

Committed patchset #1 (id:1) manually as
1cd384140daa0f30a3df5170903018a761028397 (presubmit successful).

[fbarchard1, 2016-10-05 18:44:52]

gn gen out/Release "--args=is_debug=false target_os=\"android\"
target_cpu=\"arm64\""
time ninja -j7 -v -C out/Release

Was
real	4m21.449s
Done. Made 827 targets from 101 files in 527ms
3290 objects

Now
real	2m16.326s
Done. Made 828 targets from 101 files in 559ms
1729 objects