Make the allocator_features gyp target target-only

Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header at
build time. In host/target builds, both the #host and #target
targets have a ninja rule for the same path, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds involving this target will not be correct;

And this CL fixes it.

BUG=593695
Committed: https://crrev.com/d19a104896da1904ac7b013a5cd6b4ffc205098d
Cr-Commit-Position: refs/heads/master@{#381289}

[Primiano Tucci (use gerrit), 2016-03-14 11:48:16]

Description was changed from

==========
Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header. In
host/target builds, both the #host and #target targets generate a
ninja rule for the same header, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds
involving this target will not be correct;

And this CL fixes it.

BUG=593695
==========

to

==========
Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header at
build time. In host/target builds, both the #host and #target 
targets have a ninja rule for the same path, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds
involving this target will not be correct;

And this CL fixes it.

BUG=593695
==========

[Primiano Tucci (use gerrit), 2016-03-14 11:48:16]

primiano@chromium.org changed reviewers:
+ brettw@chromium.org

[Primiano Tucci (use gerrit), 2016-03-14 13:49:45]

brettw PTAL, small fix to avoid duplicated generation of allocator header.

Q: is there anything needed for GN? I looked at your base_debugging_flags and it
looks like there is nothing special done for gn? I guess GN knows how to handle
that situation?

[sdefresne, 2016-03-15 10:53:50]

On 2016/03/14 at 13:49:45, primiano wrote:
> brettw PTAL, small fix to avoid duplicated generation of allocator header.
> 
> Q: is there anything needed for GN? I looked at your base_debugging_flags and
it looks like there is nothing special done for gn? I guess GN knows how to
handle that situation?

primiano: no, gn template for generating the feature header flags correctly deal
with different toolset (the root_gen_dir is different when using a non-default
toolset).

[brettw, 2016-03-15 17:01:55]

lgtm

[Primiano Tucci (use gerrit), 2016-03-15 18:04:48]

The CQ bit was checked by primiano@chromium.org

[commit-bot: I haz the power, 2016-03-15 18:05:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1794943006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1794943006/20001

[commit-bot: I haz the power, 2016-03-15 19:47:36]

Description was changed from

==========
Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header at
build time. In host/target builds, both the #host and #target 
targets have a ninja rule for the same path, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds
involving this target will not be correct;

And this CL fixes it.

BUG=593695
==========

to

==========
Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header at
build time. In host/target builds, both the #host and #target 
targets have a ninja rule for the same path, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds
involving this target will not be correct;

And this CL fixes it.

BUG=593695
==========

[commit-bot: I haz the power, 2016-03-15 19:47:37]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-03-15 19:50:16]

Description was changed from

==========
Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header at
build time. In host/target builds, both the #host and #target 
targets have a ninja rule for the same path, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds
involving this target will not be correct;

And this CL fixes it.

BUG=593695
==========

to

==========
Make the allocator_features gyp target target-only

allocator_features uses buildflag_header to generate a header at
build time. In host/target builds, both the #host and #target
targets have a ninja rule for the same path, which is bad.
This CL makes allocator_features follow the same pattern of
base_debugging_flags (target-only, everything else explicitly refers
to the #target veriant)

I verified that the problem reproduces without this patch
by doing:
$ build/gyp_chromium -DOS=android -Duse_experimental_allocator_shim=1
$ ninja -w dupbuild=err -n -C out_android/Release/ all
ninja: warning: multiple rules generate gen/base/allocator/features.h. builds
involving this target will not be correct;

And this CL fixes it.

BUG=593695

Committed: https://crrev.com/d19a104896da1904ac7b013a5cd6b4ffc205098d
Cr-Commit-Position: refs/heads/master@{#381289}
==========

[commit-bot: I haz the power, 2016-03-15 19:50:17]

Patchset 2 (id:??) landed as
https://crrev.com/d19a104896da1904ac7b013a5cd6b4ffc205098d
Cr-Commit-Position: refs/heads/master@{#381289}