Add system-level routing

We now respect the "route" field in Intents to load a route other than '/'.
Also, use popRoute rather than events to indicate that the framework has asked
us to go back.

sky/engine/bindings/dart_vm_entry_points.txt

 dart:io,::,_setupHooks
 dart:mojo.internal,MojoHandleWatcher,_start
 dart:ui,::,_beginFrame
-dart:ui,::,_dispatchEvent
 dart:ui,::,_dispatchPointerPacket
 dart:ui,::,_getCreateTimerClosure
 dart:ui,::,_getGetBaseURLClosure
 dart:ui,::,_getMainClosure
 dart:ui,::,_getPrintClosure
 dart:ui,::,_getScheduleMicrotaskClosure
+dart:ui,::,_popRoute
+dart:ui,::,_pushRoute
 dart:ui,::,_updateWindowMetrics
 dart:ui,Canvas,Canvas.
 dart:ui,Drawable,Drawable.

sky/engine/core/dart/hooks.dart

@@ -20,9 +20,19 @@ void _updateWindowMetrics(double devicePixelRatio,
     window.onMetricsChanged();
 }
 
-void _dispatchEvent(String eventType, double timeStamp) {
+void _pushRoute(String route) {
+  assert(window.defaultRouteName == null);
+  window.defaultRouteName = route;
+  // TODO(abarth): If we ever start calling _pushRoute other than before main,
+  // we should add a change notification callback.
+}
+
+void _popRoute() {
+  if (window.onPopRoute != null)
+    window.onPopRoute();
+  // TODO(abarth): Remove after engine roll.
   if (window.onEvent != null)
-    window.onEvent(eventType, timeStamp);
+    window.onEvent('back', 0.0);
 }
 
 void _dispatchPointerPacket(ByteData serializedPacket) {

sky/engine/core/dart/window.dart

@@ -31,10 +31,13 @@ class Window {
   WindowPadding _padding;
 
   _FrameCallback onBeginFrame;
-  _EventCallback onEvent;
+  _EventCallback onEvent; // TODO(abarth): Remove.
   _PointerPacketCallback onPointerPacket;
   VoidCallback onMetricsChanged;
 
+  String defaultRouteName;
+  VoidCallback onPopRoute;
+
   void scheduleFrame() native "Window_scheduleFrame";
   void render(Scene scene) native "Window_render";
 }

sky/engine/core/window/window.cc

@@ -66,18 +66,26 @@ void Window::UpdateWindowMetrics(const SkyDisplayMetrics& metrics) {
   });
 }
 
-void Window::DispatchEvent(const String& event_type, double time_stamp) {
+void Window::PushRoute(const std::string& route) {
   DartState* dart_state = library_.dart_state().get();
   if (!dart_state)
     return;
   DartState::Scope scope(dart_state);
 
-  DartInvokeField(library_.value(), "_dispatchEvent", {
-    DartConverter<String>::ToDart(dart_state, event_type),
-    ToDart(time_stamp)
+  DartInvokeField(library_.value(), "_pushRoute", {
+    StdStringToDart(route),
   });
 }
 
+void Window::PopRoute() {
+  DartState* dart_state = library_.dart_state().get();
+  if (!dart_state)
+    return;
+  DartState::Scope scope(dart_state);
+
+  DartInvokeField(library_.value(), "_popRoute", {});
+}
+
 void Window::DispatchPointerPacket(const pointer::PointerPacketPtr& packet) {
   DartState* dart_state = library_.dart_state().get();
   if (!dart_state)

sky/engine/core/window/window.h

@@ -33,10 +33,12 @@ class Window {
 
   void DidCreateIsolate();
   void UpdateWindowMetrics(const SkyDisplayMetrics& metrics);
-  void DispatchEvent(const String& event_type, double time_stamp);
   void DispatchPointerPacket(const pointer::PointerPacketPtr& packet);
   void BeginFrame(base::TimeTicks frameTime);
 
+  void PushRoute(const std::string& route);
+  void PopRoute();
+
   static void RegisterNatives(DartLibraryNatives* natives);
 
  private:

sky/engine/public/sky/sky_view.cc

@@ -33,6 +33,14 @@ void SkyView::SetDisplayMetrics(const SkyDisplayMetrics& metrics) {
   GetWindow()->UpdateWindowMetrics(display_metrics_);
 }
 
+void SkyView::PushRoute(const std::string& route) {
+  GetWindow()->PushRoute(route);
+}
+
+void SkyView::PopRoute() {
+  GetWindow()->PopRoute();
+}
+
 void SkyView::CreateView(const String& name) {
   DCHECK(!dart_controller_);
 
@@ -68,14 +76,6 @@ std::unique_ptr<sky::compositor::LayerTree> SkyView::BeginFrame(
   return std::move(layer_tree_);
 }
 
-void SkyView::HandleInputEvent(const WebInputEvent& inputEvent) {
-  TRACE_EVENT0("input", "SkyView::HandleInputEvent");
-
-  if (inputEvent.type == WebInputEvent::Back) {
-    GetWindow()->DispatchEvent("back", inputEvent.timeStampMS);
-  }
-}
-
 void SkyView::HandlePointerPacket(const pointer::PointerPacketPtr& packet) {
   TRACE_EVENT0("input", "SkyView::HandlePointerPacket");
   GetWindow()->DispatchPointerPacket(packet);

sky/engine/public/sky/sky_view.h

@@ -38,6 +38,8 @@ class SkyView : public WindowClient {
 
   const SkyDisplayMetrics& display_metrics() const { return display_metrics_; }
   void SetDisplayMetrics(const SkyDisplayMetrics& metrics);
+  void PushRoute(const std::string& route);
+  void PopRoute();
 
   std::unique_ptr<sky::compositor::LayerTree> BeginFrame(
       base::TimeTicks frame_time);
@@ -50,7 +52,6 @@ class SkyView : public WindowClient {
   void RunFromSnapshot(const WebString& name,
                        mojo::ScopedDataPipeConsumerHandle snapshot);
 
-  void HandleInputEvent(const WebInputEvent& event);
   void HandlePointerPacket(const pointer::PointerPacketPtr& packet);
 
   void StartDartTracing();

sky/services/engine/sky_engine.mojom

@@ -36,9 +36,11 @@ interface SkyEngine {
   OnActivityResumed();
 
   OnViewportMetricsChanged(ViewportMetrics metrics);
-  OnInputEvent(InputEvent event);
   OnPointerPacket(pointer.PointerPacket packet);
 
+  PushRoute(string route);
+  PopRoute();
+
   RunFromFile(string main, string package_root);
   RunFromPrecompiledSnapshot(string path);
   RunFromSnapshot(string path);

sky/shell/platform/android/org/domokit/sky/shell/SkyActivity.java

@@ -81,9 +81,7 @@ public class SkyActivity extends Activity {
     @Override
     public void onBackPressed() {
         if (mView != null) {
-            InputEvent event = new InputEvent();
-            event.type = EventType.BACK;
-            mView.getEngine().onInputEvent(event);
+            mView.getEngine().popRoute();
             return;
         }
         super.onBackPressed();
@@ -140,6 +138,9 @@ public class SkyActivity extends Activity {
 
         if (Intent.ACTION_RUN.equals(action)) {
             mView.getEngine().runFromBundle(intent.getDataString());
+            String route = intent.getStringExtra("route");
+            if (route != null)
+                mView.getEngine().pushRoute(route);
             return true;
         }
 

sky/shell/ui/engine.cc

@@ -143,19 +143,6 @@ void Engine::OnViewportMetricsChanged(ViewportMetricsPtr metrics) {
     sky_view_->SetDisplayMetrics(display_metrics_);
 }
 
-void Engine::OnInputEvent(InputEventPtr event) {
-  TRACE_EVENT0("flutter", "Engine::OnInputEvent");
-
-  if (event->type != EventType::BACK)
-    return;
-
-  scoped_ptr<blink::WebInputEvent> web_event(blink::WebInputEvent::create());
-  web_event->type = blink::WebInputEvent::Back;
-  web_event->timeStampMS = currentTimeMS();
-  if (sky_view_)
-    sky_view_->HandleInputEvent(*web_event);
-}
-
 void Engine::OnPointerPacket(pointer::PointerPacketPtr packet) {
   TRACE_EVENT0("flutter", "Engine::OnPointerPacket");
 
@@ -175,6 +162,8 @@ void Engine::RunFromLibrary(const std::string& name) {
   sky_view_->RunFromLibrary(blink::WebString::fromUTF8(name),
                             dart_library_provider_.get());
   sky_view_->SetDisplayMetrics(display_metrics_);
+  if (!initial_route_.empty())
+    sky_view_->PushRoute(initial_route_);
 }
 
 void Engine::RunFromSnapshotStream(
@@ -184,6 +173,8 @@ void Engine::RunFromSnapshotStream(
   sky_view_->CreateView(blink::WebString::fromUTF8(name));
   sky_view_->RunFromSnapshot(blink::WebString::fromUTF8(name), snapshot.Pass());
   sky_view_->SetDisplayMetrics(display_metrics_);
+  if (!initial_route_.empty())
+    sky_view_->PushRoute(initial_route_);
 }
 
 void Engine::RunFromPrecompiledSnapshot(const mojo::String& bundle_path) {
@@ -196,6 +187,8 @@ void Engine::RunFromPrecompiledSnapshot(const mojo::String& bundle_path) {
   sky_view_->CreateView("http://localhost");
   sky_view_->RunFromPrecompiledSnapshot();
   sky_view_->SetDisplayMetrics(display_metrics_);
+  if (!initial_route_.empty())
+    sky_view_->PushRoute(initial_route_);
 }
 
 void Engine::RunFromFile(const mojo::String& main,
@@ -230,6 +223,18 @@ void Engine::RunFromAssetBundle(const mojo::String& url,
                                        weak_factory_.GetWeakPtr(), url_str));
 }
 
+void Engine::PushRoute(const mojo::String& route) {
+  if (sky_view_)
+    sky_view_->PushRoute(route);
+  else
+    initial_route_ = route;
+}
+
+void Engine::PopRoute() {
+  if (sky_view_)
+    sky_view_->PopRoute();
+}
+
 void Engine::OnActivityPaused() {
   activity_running_ = false;
   StopAnimator();

sky/shell/ui/engine.h

@@ -61,7 +61,6 @@ class Engine : public UIDelegate,
   // SkyEngine implementation:
   void SetServices(ServicesDataPtr services) override;
   void OnViewportMetricsChanged(ViewportMetricsPtr metrics) override;
-  void OnInputEvent(InputEventPtr event) override;
   void OnPointerPacket(pointer::PointerPacketPtr packet) override;
 
   void RunFromFile(const mojo::String& main,
@@ -71,7 +70,8 @@ class Engine : public UIDelegate,
   void RunFromBundle(const mojo::String& path) override;
   void RunFromAssetBundle(const mojo::String& url,
                           mojo::asset_bundle::AssetBundlePtr bundle) override;
-
+  void PushRoute(const mojo::String& route) override;
+  void PopRoute() override;
   void OnActivityPaused() override;
   void OnActivityResumed() override;
 
@@ -96,6 +96,7 @@ class Engine : public UIDelegate,
   std::unique_ptr<blink::SkyView> sky_view_;
 
   gfx::Size physical_size_;
+  std::string initial_route_;
   blink::SkyDisplayMetrics display_metrics_;
   mojo::Binding<SkyEngine> binding_;