[Mac/GN] Add new template for creating .plugin loadable modules.

ppapi/BUILD.gn

Index: ppapi/BUILD.gn
diff --git a/ppapi/BUILD.gn b/ppapi/BUILD.gn
index 6cac3cf42d34918575fb5b24fd873b6998b8528e..9ae8d5f78f54e0d79628076adc68aa21015069bd 100644
--- a/ppapi/BUILD.gn
+++ b/ppapi/BUILD.gn
@@ -7,6 +7,10 @@ import("//build/config/features.gni")
 assert(!is_android || enable_plugins,
        "//ppapi should not be referenced when is_android && !enable_plugins")
 
+if (is_mac) {
+  import("//build/config/mac/rules.gni")
+}
+
 copy("copy_test_files") {
   visibility = [ ":*" ]
   sources = [
@@ -72,7 +76,7 @@ shared_library("power_saver_test_plugin") {
   ]
 }
 
-loadable_module("blink_deprecated_test_plugin") {
+source_set("blink_deprecated_test_plugin_sources") {
   sources = [
     "tests/blink_deprecated_test_plugin.cc",
   ]
@@ -85,7 +89,21 @@ loadable_module("blink_deprecated_test_plugin") {
   ]
 }
 
-loadable_module("blink_test_plugin") {
+if (!is_mac) {
+  loadable_module("blink_deprecated_test_plugin") {
+    deps = [
+      ":blink_deprecated_test_plugin_sources",
+    ]
+  }
+} else {
+  mac_plugin_bundle("blink_deprecated_test_plugin") {
+    deps = [
+      ":blink_deprecated_test_plugin_sources",
+    ]
+  }
+}
+
+source_set("blink_test_plugin_sources") {
   sources = [
     "tests/blink_test_plugin.cc",
   ]
@@ -98,6 +116,20 @@ loadable_module("blink_test_plugin") {
   ]
 }
 
+if (!is_mac) {
+  loadable_module("blink_test_plugin") {
+    deps = [
+      ":blink_test_plugin_sources",
+    ]
+  }
+} else {
+  mac_plugin_bundle("blink_test_plugin") {
+    deps = [
+      ":blink_test_plugin_sources",
+    ]
+  }
+}
+
 test("ppapi_unittests") {
   sources = [
     "host/resource_message_filter_unittest.cc",