[iOS] Fix build always considered dirty.

[iOS] Fix build always considered dirty.

Fix build when dSYM generation is enabled and output is a thin binary
by correctly informing gn and ninja of the location where the .dSYM
file is generated.

When defining "dsym_switch" in the toolchain definition, the value of
root_out_dir is not yet known (it is only known later when we know if
the toolchain is the default toolchain or not), so use {{root_out_dir}}
to lazily perform the expansion when the information is known.

When determining whether dSYM generation is enabled in the toolchain
definition, look at "toochain_os" instead of "is_ios" as "is_ios" is
defined based on target_os (i.e. is incorrect in the toolchain).

Use output_dir/output_name instead of using rebase_path() to generate
an output name containing directory information because 1. this is a
hack that output_dir was introduced to fix, 2. link tool and ninja do
not agree about the location of the .dSYM file.

BUG=630901
Committed: https://crrev.com/92754a40e7bd74f5a4b3437d33fa4d90068c01d2
Cr-Commit-Position: refs/heads/master@{#407737}

[sdefresne, 2016-07-25 15:36:01]

The CQ bit was checked by sdefresne@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-25 15:36:11]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[sdefresne, 2016-07-25 15:38:42]

sdefresne@chromium.org changed reviewers:
+ dpranke@chromium.org, justincohen@chromium.org

[sdefresne, 2016-07-25 15:38:42]

sdefresne@chromium.org changed required reviewers:
+ dpranke@chromium.org

[sdefresne, 2016-07-25 15:38:43]

Dirk: can you take a look?

Justin: FYI, thank you for the report

[commit-bot: I haz the power, 2016-07-25 16:36:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-25 16:36:05]

Dry run: This issue passed the CQ dry run.

[Dirk Pranke, 2016-07-25 21:05:26]

lgtm

[sdefresne, 2016-07-26 08:44:18]

The CQ bit was checked by sdefresne@chromium.org

[commit-bot: I haz the power, 2016-07-26 08:44:41]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-26 08:47:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-26 08:49:27]

Description was changed from

==========
[iOS] Fix build always considered dirty.

Fix build when dSYM generation is enabled and output is a thin binary
by correctly informing gn and ninja of the location where the .dSYM
file is generated.

When defining "dsym_switch" in the toolchain definition, the value of
root_out_dir is not yet known (it is only known later when we know if
the toolchain is the default toolchain or not), so use {{root_out_dir}}
to lazily perform the expansion when the information is known.

When determining whether dSYM generation is enabled in the toolchain
definition, look at "toochain_os" instead of "is_ios" as "is_ios" is
defined based on target_os (i.e. is incorrect in the toolchain).

Use output_dir/output_name instead of using rebase_path() to generate
an output name containing directory information because 1. this is a
hack that output_dir was introduced to fix, 2. link tool and ninja do
not agree about the location of the .dSYM file.

BUG=630901
==========

to

==========
[iOS] Fix build always considered dirty.

Fix build when dSYM generation is enabled and output is a thin binary
by correctly informing gn and ninja of the location where the .dSYM
file is generated.

When defining "dsym_switch" in the toolchain definition, the value of
root_out_dir is not yet known (it is only known later when we know if
the toolchain is the default toolchain or not), so use {{root_out_dir}}
to lazily perform the expansion when the information is known.

When determining whether dSYM generation is enabled in the toolchain
definition, look at "toochain_os" instead of "is_ios" as "is_ios" is
defined based on target_os (i.e. is incorrect in the toolchain).

Use output_dir/output_name instead of using rebase_path() to generate
an output name containing directory information because 1. this is a
hack that output_dir was introduced to fix, 2. link tool and ninja do
not agree about the location of the .dSYM file.

BUG=630901

Committed: https://crrev.com/92754a40e7bd74f5a4b3437d33fa4d90068c01d2
Cr-Commit-Position: refs/heads/master@{#407737}
==========

[commit-bot: I haz the power, 2016-07-26 08:49:28]

Patchset 1 (id:??) landed as
https://crrev.com/92754a40e7bd74f5a4b3437d33fa4d90068c01d2
Cr-Commit-Position: refs/heads/master@{#407737}