apple: Convert GN libs lists to frameworks in //google_apis.

GN recently added support for Apple frameworks to link, rather than
overloading the libs lists. This pulls .frameworks out of the libs
lists, so that GN can stop supporting .frameworks in libs in the
future.

Bug: 1052560
Change-Id: I80e421a98f13416626d2e92dc13bd8727b422a6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2277967
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784451}

google_apis/BUILD.gn

@@ -159,7 +159,7 @@ template("google_apis_tmpl") {
       ]
       set_sources_assignment_filter(sources_assignment_filter)
 
-      libs = [ "Foundation.framework" ]
+      frameworks = [ "Foundation.framework" ]
     }
   }
 }