[iOS/OS X] Allow base::scoped_nsobject<> to be used when ARC is enabled.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 6ef6cd351494b18e4df8baf97c3e335a5a6cd235..efab95bcafc5be34e569b12d227be00e3a109a08 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -429,6 +429,7 @@ component("base") {
     "mac/scoped_aedesc.h",
     "mac/scoped_authorizationref.h",
     "mac/scoped_block.h",
+    "mac/scoped_block.mm",
     "mac/scoped_cftyperef.h",
     "mac/scoped_ioobject.h",
     "mac/scoped_ioplugininterface.h",
@@ -440,6 +441,7 @@ component("base") {
     "mac/scoped_nsautorelease_pool.h",
     "mac/scoped_nsautorelease_pool.mm",
     "mac/scoped_nsobject.h",
+    "mac/scoped_nsobject.mm",
     "mac/scoped_objc_class_swizzler.h",
     "mac/scoped_objc_class_swizzler.mm",
     "mac/scoped_sending_event.h",
@@ -1392,6 +1394,8 @@ component("base") {
       "mac/mach_logging.h",
       "mac/objc_property_releaser.h",
       "mac/objc_property_releaser.mm",
+      "mac/scoped_block.h",
+      "mac/scoped_block.mm",
       "mac/scoped_mach_port.cc",
       "mac/scoped_mach_port.h",
       "mac/scoped_mach_vm.cc",
@@ -1399,8 +1403,10 @@ component("base") {
       "mac/scoped_nsautorelease_pool.h",
       "mac/scoped_nsautorelease_pool.mm",
       "mac/scoped_nsobject.h",
+      "mac/scoped_nsobject.mm",
       "mac/scoped_objc_class_swizzler.h",
       "mac/scoped_objc_class_swizzler.mm",
+      "mac/scoped_typeref.h",
       "memory/shared_memory_posix.cc",
       "message_loop/message_pump_mac.h",
       "message_loop/message_pump_mac.mm",
@@ -1650,6 +1656,22 @@ bundle_data("base_unittests_bundle_data") {
   ]
 }
 
+if (is_ios || is_mac) {
+  source_set("base_unittests_arc") {
+    testonly = true
+    set_sources_assignment_filter([])
+    sources = [
+      "mac/scoped_nsobject_unittest_arc.mm",
+    ]
+    set_sources_assignment_filter(sources_assignment_filter)
+    configs += [ "//build/config/compiler:enable_arc" ]
+    deps = [
+      ":base",
+      "//testing/gtest",
+    ]
+  }
+}
+
 test("base_unittests") {
   sources = [
     "allocator/tcmalloc_unittest.cc",
@@ -1920,6 +1942,10 @@ test("base_unittests") {
     "//third_party/icu",
   ]
 
+  if (is_ios || is_mac) {
+    deps += [ ":base_unittests_arc" ]
+  }
+
   public_deps = [
     ":base_unittests_bundle_data",
   ]