Make unit_tests compile in Mac GN

components/crash/content/app/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 source_set("lib") {
   sources = [
     "crash_keys_win.cc",
     "crash_keys_win.h",
     "crash_reporter_client.cc",
     "crash_reporter_client.h",
   ]
 
   include_dirs = [ "../../../../breakpad/src" ]
 }
 
 # Note: if you depend on this target, you need to either link in
 # content.gyp:content_common, or add content/public/common/content_switches.cc
 # to your sources.
 #
 # GYP version: components/crash.gypi:crash_component
 source_set("app") {
   sources = [
+    "crashpad_mac.h",
+    "crashpad_mac.mm",
+  ]
+
+  defines = [ "CRASH_IMPLEMENTATION" ]
+
+  deps = [
+    ":app_non_mac",
+    "//base",
+  ]
+
+  if (is_mac) {
+    deps += [ "//third_party/crashpad/crashpad/client" ]
+  }
+}
+
+# TODO(mark): https://crbug.com/466890: merge this target with
+# crash_component.
+#
+# This is a temporary base target that is depended on by both
+# crash_component and crash_component_breakpad_mac_to_be_deleted. It
+# provides everything common to both of those targets. For a short period,
+# there are two Mac crash component implementations. The new one uses a
+# Crashpad implementation and is used by Chrome. The old one uses a
+# Breakpad implementation and is used by content_shell. Consumers should
+# depend on the desired target. All three targets behave identically on
+# non-Mac. When content_shell and any other consumers are migrated to the
+# Crashpad implementation on Mac, crash_component will merge back into
+# this target, crash_component_non_mac, which will be renamed
+# crash_component. crash_component_breakpad_mac_to_be_deleted will be
+# deleted.
+#
+# While this situation exists:
+#
+# Do not depend on this target directly! Depend on
+# crash_component_breakpad_mac_to_be_deleted for old Breakpad behavior on
+# all platforms, or preferably, depend on crash_component to get Breakpad
+# everywhere except for Mac, where you will get Crashpad.
+source_set("app_non_mac") {
+  visibility = [ ":*" ]
+
+  sources = [
     "breakpad_linux_impl.h",
-    "breakpad_mac.h",
-    "breakpad_mac.mm",
     "breakpad_win.cc",
     "breakpad_win.h",
     "hard_error_handler_win.cc",
     "hard_error_handler_win.h",
   ]
 
   if (is_android) {
     libs = [ "log" ]
   }
 
   if (is_android || is_linux) {
     # Want these files on both Linux and Android.
     set_sources_assignment_filter([])
     sources += [
       "breakpad_linux.cc",
       "breakpad_linux.h",
     ]
   }
 
   defines = [ "CRASH_IMPLEMENTATION" ]
 
   deps = [
+    ":lib",
     "//base",
     "//base:base_static",
-    ":lib",
   ]
 
   if (is_android) {
     defines += [ "CHROME_BUILD_ID=" + android_chrome_build_id ]
   }
 
-  if (is_mac) {
-    deps += [ "//breakpad" ]
-  } else if (is_win) {
+  if (is_win) {
     deps += [
       "//sandbox",
       "//breakpad:breakpad_handler",
 
       #'../breakpad/breakpad.gyp:breakpad_sender',  TODO(GYP)
     ]
   } else if (is_posix && !is_ios) {
     deps += [ "//breakpad:client" ]
   }
 }
 
-source_set("test_support") {
+# TODO(mark): https://crbug.com/466890: remove this target.
+#
+# This is a temporary target provided for Mac Breakpad users that have not
+# yet migrated to Crashpad (namely content_shell). This target will be
+# removed shortly and all consumers will be expected to use Crashpad as
+# the Mac crash-reporting client. See the comment in the
+# crash_component_non_mac target for more details.
+source_set("app_breakpad_mac_to_be_deleted") {
   deps = [
-    ":lib",
+    ":app_non_mac",
   ]
+
+  if (is_mac) {
+    sources = [
+      "breakpad_mac.h",
+      "breakpad_mac.mm",
+    ]
+
+    defines = [ "CRASH_IMPLEMENTATION" ]
+
+    deps += [
+      "//base",
+      "//base:base_static",
+      "//breakpad",
+    ]
+  }
 }