Make `content` target build without unused data members on Linux.

mojo/runner/host/child_process.cc

 // Copyright 2014 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.
 
 #include "mojo/runner/host/child_process.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 236 matching lines @@
 
   void ExitNow(int32_t exit_code) override {
     DVLOG(2) << "ChildControllerImpl::ExitNow(" << exit_code << ")";
     _exit(exit_code);
   }
 
  private:
   ChildControllerImpl(AppContext* app_context,
                       base::NativeLibrary app_library,
                       const Blocker::Unblocker& unblocker)
-      : app_context_(app_context),
-        app_library_(app_library),
-        unblocker_(unblocker),
-        channel_info_(nullptr),
-        binding_(this) {}
+      : app_library_(app_library), unblocker_(unblocker), binding_(this) {}
 
   static void StartAppOnMainThread(
       base::NativeLibrary app_library,
       InterfaceRequest<Application> application_request) {
     if (!RunNativeApplication(app_library, std::move(application_request))) {
       LOG(ERROR) << "Failure to RunNativeApplication()";
     }
   }
 
   base::ThreadChecker thread_checker_;
-  AppContext* const app_context_;
   base::NativeLibrary app_library_;
   Blocker::Unblocker unblocker_;
   StartAppCallback on_app_complete_;
 
-  embedder::ChannelInfo* channel_info_;
   Binding<ChildController> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildControllerImpl);
 };
 
 #if defined(OS_LINUX) && !defined(OS_ANDROID)
 scoped_ptr<mojo::runner::LinuxSandbox> InitializeSandbox() {
   using sandbox::syscall_broker::BrokerFilePermission;
   // Warm parts of base in the copy of base in the mojo runner.
   base::RandUint64();
@@ skipping 104 matching lines @@
   // This will block, then run whatever the controller wants.
   blocker.Block();
 
   app_context.Shutdown();
 
   return 0;
 }
 
 }  // namespace runner
 }  // namespace mojo