Add support for Mac/iOS application bundles to GN tool.

tools/gn/toolchain.h

Index: tools/gn/toolchain.h
diff --git a/tools/gn/toolchain.h b/tools/gn/toolchain.h
index b49153b75205210f2dcc0165e51d2f563ab9327a..2ab77ae343792d34df7230d0ed369d13bc661c23 100644
--- a/tools/gn/toolchain.h
+++ b/tools/gn/toolchain.h
@@ -44,6 +44,7 @@ class Toolchain : public Item {
     TYPE_LINK,
     TYPE_STAMP,
     TYPE_COPY,
+    TYPE_COPY_BUNDLE_DATA,
 
     TYPE_NUMTYPES  // Must be last.
   };
@@ -60,6 +61,7 @@ class Toolchain : public Item {
   static const char* kToolLink;
   static const char* kToolStamp;
   static const char* kToolCopy;
+  static const char* kToolCopyBundleData;
 
   Toolchain(const Settings* settings, const Label& label);
   ~Toolchain() override;