content: Refactor ChildThreadImpl::Options

content/child/child_thread_impl.h

Index: content/child/child_thread_impl.h
diff --git a/content/child/child_thread_impl.h b/content/child/child_thread_impl.h
index 4016861820ae15b4ca009ca52a801256fe642471..f614f0263e5aebfe0a409d148bd40af9a7defacd 100644
--- a/content/child/child_thread_impl.h
+++ b/content/child/child_thread_impl.h
@@ -61,17 +61,7 @@ class CONTENT_EXPORT ChildThreadImpl
     : public IPC::Listener,
       virtual public ChildThread {
  public:
-  struct CONTENT_EXPORT Options {
-    Options();
-    explicit Options(bool mojo);
-    Options(std::string name, bool mojo);
-    ~Options();
-
-    std::string channel_name;
-    bool use_mojo_channel;
-    bool in_browser_process;
-    std::vector<IPC::MessageFilter*> startup_filters;
-  };
+  struct CONTENT_EXPORT Options;
 
   // Creates the thread.
   ChildThreadImpl();
@@ -305,6 +295,37 @@ class CONTENT_EXPORT ChildThreadImpl
   DISALLOW_COPY_AND_ASSIGN(ChildThreadImpl);
 };
 
+struct ChildThreadImpl::Options {
+  ~Options();
+
+  class Builder;
+
+  std::string channel_name;
+  bool use_mojo_channel;
+  bool in_browser_process;
+  std::vector<IPC::MessageFilter*> startup_filters;
+
+ private:
+  Options();
+};
+
+class ChildThreadImpl::Options::Builder {
+ public:
+  Builder();
+
+  Builder& InBrowserProcess(bool in_browser_process);
+  Builder& UseMojoChannel(bool use_mojo_channel);
+  Builder& WithChannelName(const std::string& channel_name);
+  Builder& AddStartupFilter(IPC::MessageFilter* filter);
+
+  Options Build();
+
+ private:
+  struct Options options_;
+
+  DISALLOW_COPY_AND_ASSIGN(Builder);
+};
+
 }  // namespace content
 
 #endif  // CONTENT_CHILD_CHILD_THREAD_IMPL_H_