[Android] Only set recommended flags if they are unset

[Android] Only set recommended flags if they are unset

This allows developers to force the values of individual flags in their
chrome/supplement.gypi. Add documentation for how a user can do that.

Also add a comment about the fastbuild option, but do not ever set it
by default.

NOTRY=true
BUG=158821
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=195334

[Yaron, 2013-04-19 22:44:27]

https://codereview.chromium.org/14366023/diff/2001/build/android/developer_re...
File build/android/developer_recommended_flags.gypi (right):

https://codereview.chromium.org/14366023/diff/2001/build/android/developer_re...
build/android/developer_recommended_flags.gypi:7: # These can be used by copying
this file to $CHROME_SRC/chrome/supplement.gypi.
Why encourage people to use chrome/supplement.gypi when it'll cause a dirty tree
and may accidentally get included in the commit? ISTM that the home-dir approach
is safer.

[cjhopman, 2013-04-19 22:51:18]

https://codereview.chromium.org/14366023/diff/2001/build/android/developer_re...
File build/android/developer_recommended_flags.gypi (right):

https://codereview.chromium.org/14366023/diff/2001/build/android/developer_re...
build/android/developer_recommended_flags.gypi:7: # These can be used by copying
this file to $CHROME_SRC/chrome/supplement.gypi.
On 2013/04/19 22:44:27, Yaron wrote:
> Why encourage people to use chrome/supplement.gypi when it'll cause a dirty
tree
> and may accidentally get included in the commit? ISTM that the home-dir
approach
> is safer.

chrome/supplement.gypi is ignored in .gitignore specifically so that it can be
used for user-specified, per-repo settings. Also using chrome/supplement.gypi
allows including this file directly.

[Yaron, 2013-04-19 23:26:02]

lgtm

Cool! Didn't know

[commit-bot: I haz the power, 2013-04-19 23:26:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/cjhopman@chromium.org/14366023/2001

[commit-bot: I haz the power, 2013-04-19 23:27:08]

Change committed as 195334