Get a minimal unit_tests target building and running for iOS

chrome/common_constants.gyp

Index: chrome/common_constants.gyp
diff --git a/chrome/common_constants.gyp b/chrome/common_constants.gyp
index e5f6d619a413615f1f1e73636568a7781e4a9452..4e3915818ad2afcd834e1cc9d5e188c70374a0d9 100644
--- a/chrome/common_constants.gyp
+++ b/chrome/common_constants.gyp
@@ -65,6 +65,15 @@
         '../base/base.gyp:base',
         '../third_party/widevine/cdm/widevine_cdm.gyp:widevine_cdm_version_h',
       ],
+      'target_conditions': [
+        ['OS=="ios"', {
+          # iOS needs chrome_paths_mac, which is excluded by filename rules;
+          # re-add it in target_conditionals so it's after that exclusion.

[Nico, 2012/11/15 18:01:33]

Is there a file name rule for files that are used on both mac and ios?

It's a bit confusing that _mac.mm is excluded on iOS, but OS_MACOSX is
apparently true on iOS.

[stuartmorgan, 2012/11/15 18:23:11]

No. I spoke to Mark about this quite a while ago, and suggested _apple, but he
was strongly opposed and wanted us to just include specific _mac files.
Agreed, but our feeling is that the alternative is worse. There's a whole lot of
_mac and /mac/ files that we don't want, and re-excluding them would be more
painful that doing targeted includes. OS_MACOSX and OS_IOS follows the Apple
convention used for availability macro headers, where OS X is always true, even
on iOS. And within files we do use, MACOSX is often the right thing for us,
since there is a lot of shared code in Foundation and such.

I can try to get numbers on both the ifdef and the files if you want, and we can
re-open the discussion. I really don't think we should make our macros work
differently than the exactly corresponding Apple macros though.

[Nico, 2012/11/15 18:27:22]

It's ok, I was just curious.

+          'sources/': [
+            ['include', '^common/chrome_paths_mac\\.mm$'],
+          ],
+        }],
+      ],
       'conditions': [
         ['toolkit_uses_gtk == 1', {
           'dependencies': ['../build/linux/system.gyp:gtk'],