Introduce very beginning of navigation

mojo/examples/nesting_app/nesting_app.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 "base/basictypes.h"
 #include "base/bind.h"
+#include "base/strings/stringprintf.h"
 #include "mojo/examples/window_manager/window_manager.mojom.h"
 #include "mojo/public/cpp/application/application.h"
+#include "mojo/services/navigation/navigation.mojom.h"
 #include "mojo/services/public/cpp/view_manager/view.h"
 #include "mojo/services/public/cpp/view_manager/view_manager.h"
 #include "mojo/services/public/cpp/view_manager/view_manager_delegate.h"
 #include "mojo/services/public/cpp/view_manager/view_observer.h"
 #include "mojo/services/public/cpp/view_manager/view_tree_node.h"
 #include "mojo/services/public/cpp/view_manager/view_tree_node_observer.h"
 #include "ui/events/event_constants.h"
+#include "url/gurl.h"
 
 using mojo::view_manager::View;
 using mojo::view_manager::ViewManager;
 using mojo::view_manager::ViewManagerDelegate;
 using mojo::view_manager::ViewObserver;
 using mojo::view_manager::ViewTreeNode;
 using mojo::view_manager::ViewTreeNodeObserver;
 
 namespace mojo {
 namespace examples {
 
+namespace {
+const char kEmbeddedAppURL[] = "mojo:mojo_embedded_app";
+}
+
 // An app that embeds another app.
 class NestingApp : public Application,
                    public ViewManagerDelegate,
                    public ViewObserver {
  public:
-  NestingApp() {}
+  NestingApp() : nested_(NULL) {}
   virtual ~NestingApp() {}
 
  private:
+  class ViewNavigator : public InterfaceImpl<navigation::ViewNavigator> {
+   public:
+    explicit ViewNavigator(NestingApp* app) : app_(app) {}
+
+   private:
+    virtual void Navigate(uint32 node_id,
+                          navigation::NavigationDetailsPtr details) OVERRIDE {
+      GURL url(details->url.To<std::string>());
+      if (!url.is_valid()) {
+        LOG(ERROR) << "URL is invalid.";
+        return;
+      }
+      app_->color_ = url.path().substr(1);
+      app_->NavigateChild();
+    }
+
+    NestingApp* app_;
+  };
+
   // Overridden from Application:
   virtual void Initialize() MOJO_OVERRIDE {
     ViewManager::Create(this, this);
     ConnectTo<IWindowManager>("mojo:mojo_window_manager", &window_manager_);
+    AddService<ViewNavigator>(this);
   }
 
   // Overridden from ViewManagerDelegate:
   virtual void OnRootAdded(ViewManager* view_manager,
                            ViewTreeNode* root) OVERRIDE {
     View* view = View::Create(view_manager);
     root->SetActiveView(view);
     view->SetColor(SK_ColorCYAN);
     view->AddObserver(this);
 
-    ViewTreeNode* nested = ViewTreeNode::Create(view_manager);
-    root->AddChild(nested);
-    nested->SetBounds(gfx::Rect(20, 20, 50, 50));
-    nested->Embed("mojo:mojo_embedded_app");
+    nested_ = ViewTreeNode::Create(view_manager);
+    root->AddChild(nested_);
+    nested_->SetBounds(gfx::Rect(20, 20, 50, 50));
+    nested_->Embed(kEmbeddedAppURL);
+
+    if (!view_navigator_.get())
+      ConnectTo(kEmbeddedAppURL, &view_navigator_);
+
+    NavigateChild();
   }
+
   virtual void OnRootRemoved(ViewManager* view_manager,
                              ViewTreeNode* root) OVERRIDE {
     // TODO(beng): reap views & child nodes.
+    nested_ = NULL;
   }
 
   // Overridden from ViewObserver:
   virtual void OnViewInputEvent(View* view, const EventPtr& event) OVERRIDE {
     if (event->action == ui::ET_MOUSE_RELEASED)
       window_manager_->CloseWindow(view->node()->id());
   }
 
+  void NavigateChild() {
+    if (!color_.empty() && nested_) {
+      navigation::NavigationDetailsPtr details(
+          navigation::NavigationDetails::New());
+      details->url =
+          base::StringPrintf("%s/%s", kEmbeddedAppURL, color_.c_str());
+      view_navigator_->Navigate(nested_->id(), details.Pass());
+    }
+  }
+
+  std::string color_;
+  ViewTreeNode* nested_;
+  navigation::ViewNavigatorPtr view_navigator_;
   IWindowManagerPtr window_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(NestingApp);
 };
 
 }  // namespace examples
 
 // static
 Application* Application::Create() {
   return new examples::NestingApp;
 }
 
 }  // namespace mojo