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

tools/gn/ninja_copy_target_writer.h

Index: tools/gn/ninja_copy_target_writer.h
diff --git a/tools/gn/ninja_copy_target_writer.h b/tools/gn/ninja_copy_target_writer.h
index 9e1746ee9cc09820ebc16cf913bc96273df4c751..948884a90150553c50e7eb64084649b9f5ae8144 100644
--- a/tools/gn/ninja_copy_target_writer.h
+++ b/tools/gn/ninja_copy_target_writer.h
@@ -7,13 +7,15 @@
 
 #include "base/macros.h"
 #include "tools/gn/ninja_target_writer.h"
+#include "tools/gn/toolchain.h"
 
 class Tool;
 
 // Writes a .ninja file for a copy target type.
 class NinjaCopyTargetWriter : public NinjaTargetWriter {
  public:
-  NinjaCopyTargetWriter(const Target* target, std::ostream& out);
+  NinjaCopyTargetWriter(
+      const Target* target, std::ostream& out, Toolchain::ToolType tool_type);
   ~NinjaCopyTargetWriter() override;
 
   void Run() override;
@@ -23,6 +25,8 @@ class NinjaCopyTargetWriter : public NinjaTargetWriter {
   // name(s) into the given vector.
   void WriteCopyRules(std::vector<OutputFile>* output_files);
 
+  Toolchain::ToolType tool_type_;
+
   DISALLOW_COPY_AND_ASSIGN(NinjaCopyTargetWriter);
 };