Connect mojo:debugger to window_manager only when requested.

services/debugger/debugger.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 <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/profiler.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
@@ skipping 21 matching lines @@
 class Debugger : public mojo::ApplicationDelegate,
                     public http_server::HttpHandler {
  public:
   Debugger() : is_tracing_(false), app_(nullptr), handler_binding_(this) {}
   ~Debugger() override {}
 
  private:
   // mojo::ApplicationDelegate:
   void Initialize(mojo::ApplicationImpl* app) override {
     app_ = app;
-    app->ConnectToService("mojo:window_manager", &window_manager_);
 
     // Format: --args-for="app_url command_port"
     if (app->args().size() < 2) {
       LOG(ERROR) << "--args-for required to specify command_port";
       mojo::ApplicationImpl::Terminate();
       return;
     }
+    if (app->args().size() == 3 && app->args()[2] == "--wm") {
+      // Connect to window manager only if requested, as the user might want to
+      // run the debugger without spawning one.
+      app_->ConnectToService("mojo:window_manager", &window_manager_);
+    }
     base::StringToUint(app->args()[1], &command_port_);
     http_server::HttpServerFactoryPtr http_server_factory;
     app->ConnectToService("mojo:http_server", &http_server_factory);
 
     mojo::NetAddressPtr local_address(mojo::NetAddress::New());
     local_address->family = mojo::NET_ADDRESS_FAMILY_IPV4;
     local_address->ipv4 = mojo::NetAddressIPv4::New();
     local_address->ipv4->addr.resize(4);
     local_address->ipv4->addr[0] = 127;
     local_address->ipv4->addr[1] = 0;
@@ skipping 62 matching lines @@
   }
 
   void Load(const HandleRequestCallback& callback, std::string url) {
     url_ = url;
     Reload();
     std::string response = std::string("Loaded ") + url + "\n";
     Respond(callback, response);
   }
 
   void Reload() {
+    if (!window_manager_)
+      return;
+
     // SimpleWindowManager will wire up necessary services on our behalf.
     window_manager_->Embed(url_, nullptr, nullptr);
   }
 
   void Exit() {
     // TODO(eseidel): We should orderly shutdown once mojo can.
     exit(0);
   }
 
   void StartTracing(const HandleRequestCallback& callback) {
@@ skipping 63 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(Debugger);
 };
 
 }  // namespace debugger
 
 MojoResult MojoMain(MojoHandle application_request) {
   mojo::ApplicationRunnerChromium runner(new debugger::Debugger);
   runner.set_message_loop_type(base::MessageLoop::TYPE_IO);
   return runner.Run(application_request);
 }