Adds ability to build for asan with gn

Adds ability to build for asan with gn

BUG=none
TEST=none
R=brettw@chromium.org

Committed: https://crrev.com/fec68221196ae74b73f6c7a4c574bd33666bb7ed
Cr-Commit-Position: refs/heads/master@{#301751}

[brettw, 2014-10-28 16:59:13]

https://codereview.chromium.org/682843002/diff/20001/build/config/BUILDCONFIG.gn
File build/config/BUILDCONFIG.gn (right):

https://codereview.chromium.org/682843002/diff/20001/build/config/BUILDCONFIG...
build/config/BUILDCONFIG.gn:485: sanitizer_deps = [ "//build/sanitizers:options"
]
I think we would want this in a .gni file. But actually I had a better idea.
Just delete this and add a dep the sanitizer helper target directly. Then define
that target to be nothing when no sanitizer is enabled. I think this will look
cleaner in the deps list.

I feel like we should also change the name of the target then, so it makes the
most possible sense from the target depending on it. Maybe
//build/config/sanitizers:deps or something?

https://codereview.chromium.org/682843002/diff/20001/build/sanitizers/BUILD.gn
File build/sanitizers/BUILD.gn (right):

https://codereview.chromium.org/682843002/diff/20001/build/sanitizers/BUILD.g...
build/sanitizers/BUILD.gn:5: group("options") {
Can you put this file in //build/config/sanitizers instead? I've been putting
all GN stuff in only build/config and build/toolchain to keep it separate from
the rest of the build mess.

https://codereview.chromium.org/682843002/diff/20001/build/sanitizers/BUILD.g...
build/sanitizers/BUILD.gn:17: include_dirs = [ "../.." ]
Use absolute paths. Actually, isn't this the root path? That should already be
implicit so I think you can delete this.

[sky, 2014-10-28 18:11:24]

I think this is what you were asking for.

[brettw, 2014-10-28 23:55:16]

lgtm

https://codereview.chromium.org/682843002/diff/40001/build/config/BUILDCONFIG.gn
File build/config/BUILDCONFIG.gn (right):

https://codereview.chromium.org/682843002/diff/40001/build/config/BUILDCONFIG...
build/config/BUILDCONFIG.gn:571: if (defined(invoker.deps)) {
Can you put a comment above here
# All shared libraries must have the sanitizer deps to properly link in asan
mode (this target will be empty in other cases).

https://codereview.chromium.org/682843002/diff/40001/build/config/BUILDCONFIG...
build/config/BUILDCONFIG.gn:698: if (defined(invoker.deps)) {
Copy-and-paste comment, I think.

https://codereview.chromium.org/682843002/diff/40001/build/config/sanitizers/...
File build/config/sanitizers/BUILD.gn (right):

https://codereview.chromium.org/682843002/diff/40001/build/config/sanitizers/...
build/config/sanitizers/BUILD.gn:5: group("deps") {
Can you provide a comment here about how this is the stuff required to link into
executables and shared libraries when running under asan, and that it will
conditionally be empty in other cases so targets can unconditionally depend on
it.

[sky, 2014-10-29 00:02:30]

https://codereview.chromium.org/682843002/diff/40001/build/config/BUILDCONFIG.gn
File build/config/BUILDCONFIG.gn (right):

https://codereview.chromium.org/682843002/diff/40001/build/config/BUILDCONFIG...
build/config/BUILDCONFIG.gn:571: if (defined(invoker.deps)) {
On 2014/10/28 23:55:16, brettw wrote:
> Can you put a comment above here
> # All shared libraries must have the sanitizer deps to properly link in asan
> mode (this target will be empty in other cases).

Done.

https://codereview.chromium.org/682843002/diff/40001/build/config/BUILDCONFIG...
build/config/BUILDCONFIG.gn:698: if (defined(invoker.deps)) {
On 2014/10/28 23:55:16, brettw wrote:
> Copy-and-paste comment, I think.

Done.

https://codereview.chromium.org/682843002/diff/40001/build/config/sanitizers/...
File build/config/sanitizers/BUILD.gn (right):

https://codereview.chromium.org/682843002/diff/40001/build/config/sanitizers/...
build/config/sanitizers/BUILD.gn:5: group("deps") {
On 2014/10/28 23:55:16, brettw wrote:
> Can you provide a comment here about how this is the stuff required to link
into
> executables and shared libraries when running under asan, and that it will
> conditionally be empty in other cases so targets can unconditionally depend on
> it.

Done.

[sky, 2014-10-29 00:02:35]

The CQ bit was checked by sky@chromium.org

[commit-bot: I haz the power, 2014-10-29 00:04:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/682843002/60001

[commit-bot: I haz the power, 2014-10-29 00:53:07]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2014-10-29 00:53:46]

Patchset 4 (id:??) landed as
https://crrev.com/fec68221196ae74b73f6c7a4c574bd33666bb7ed
Cr-Commit-Position: refs/heads/master@{#301751}