[Refactor Xcode Objects] Decouple file references and indexing target.

tools/gn/xcode_object.h

 // Copyright 2016 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.
 
 #ifndef TOOLS_GN_XCODE_OBJECT_H_
 #define TOOLS_GN_XCODE_OBJECT_H_
 
 #include <iosfwd>
 #include <map>
 #include <memory>
@@ skipping 253 matching lines @@
 // PBXProject -----------------------------------------------------------------
 
 class PBXProject : public PBXObject {
  public:
   PBXProject(const std::string& name,
              const std::string& config_name,
              const std::string& source_path,
              const PBXAttributes& attributes);
   ~PBXProject() override;
 
-  void AddSourceFile(const std::string& source_path);
+  void AddSourceFileToIndexingTarget(const std::string& source_path);
+  void AddSourceFile(const std::string& source_path, PBXNativeTarget* target);
+
   void AddAggregateTarget(const std::string& name,
                           const std::string& shell_script);
-  void AddNativeTarget(const std::string& name,
-                       const std::string& type,
-                       const std::string& output_name,
-                       const std::string& output_type,
-                       const std::string& shell_script);
+  void AddIndexingTarget();
+  PBXNativeTarget* AddNativeTarget(const std::string& name,

[sdefresne, 2016/12/16 23:51:55]

Why do you change the return value of this method? Is this for a followup CL? I
do not see any change to the caller of that method, so the returned value is
unused in that CL. Can you move the change to the followup CL instead and revert
in this one (or point me to where the value is used, I may have missed it).

[liaoyuke, 2016/12/19 08:03:35]

Done. Yes, it is for a followup CL, I will move the change to later.

+                                   const std::string& type,
+                                   const std::string& output_name,
+                                   const std::string& output_type,
+                                   const std::string& shell_script);
 
   void SetProjectDirPath(const std::string& project_dir_path);
   void SetProjectRoot(const std::string& project_root);
   void AddTarget(std::unique_ptr<PBXTarget> target);
 
   // PBXObject implementation.
   PBXObjectClass Class() const override;
   std::string Name() const override;
   std::string Comment() const override;
   void Visit(PBXObjectVisitor& visitor) override;
@@ skipping 93 matching lines @@
   void Print(std::ostream& out, unsigned indent) const override;
 
  private:
   std::vector<std::unique_ptr<XCBuildConfiguration>> configurations_;
   const PBXObject* owner_reference_;
 
   DISALLOW_COPY_AND_ASSIGN(XCConfigurationList);
 };
 
 #endif  // TOOLS_GN_XCODE_OBJECT_H_