Port touch-demo.sky to Dart and make it work in SkyShell

sky/shell/apk/src/org/domokit/sky/shell/PlatformView.java

Index: sky/shell/apk/src/org/domokit/sky/shell/PlatformView.java
diff --git a/sky/shell/apk/src/org/domokit/sky/shell/PlatformView.java b/sky/shell/apk/src/org/domokit/sky/shell/PlatformView.java
index ac8879d43c07391a0bed1a0b803f0f9ac542581f..0934fc5077905f27d942d1eef154ce830fcf880a 100644
--- a/sky/shell/apk/src/org/domokit/sky/shell/PlatformView.java
+++ b/sky/shell/apk/src/org/domokit/sky/shell/PlatformView.java
@@ -5,12 +5,22 @@
 package org.domokit.sky.shell;
 
 import android.content.Context;
+import android.view.MotionEvent;
 import android.view.Surface;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
 import android.view.View;
 
 import org.chromium.base.JNINamespace;
+import org.chromium.mojo.bindings.InterfaceRequest;
+import org.chromium.mojo.system.Core;
+import org.chromium.mojo.system.Pair;
+import org.chromium.mojo.system.impl.CoreImpl;
+import org.chromium.mojom.sky.EventType;
+import org.chromium.mojom.sky.InputEvent;
+import org.chromium.mojom.sky.PointerData;
+import org.chromium.mojom.sky.PointerKind;
+import org.chromium.mojom.sky.ViewportObserver;
 
 /**
  * A view containing Sky
@@ -18,6 +28,7 @@ import org.chromium.base.JNINamespace;
 @JNINamespace("sky::shell")
 public class PlatformView extends SurfaceView {
     private long mNativePlatformView;
+    private ViewportObserver.Proxy mViewportObserver;
     private final SurfaceHolder.Callback mSurfaceCallback;
 
     public PlatformView(Context context) {
@@ -26,7 +37,7 @@ public class PlatformView extends SurfaceView {
         setFocusable(true);
         setFocusableInTouchMode(true);
 
-        mNativePlatformView = nativeAttach();
+        attach();
         assert mNativePlatformView != 0;
 
         final float density = context.getResources().getDisplayMetrics().density;
@@ -34,8 +45,8 @@ public class PlatformView extends SurfaceView {
         mSurfaceCallback = new SurfaceHolder.Callback() {
             @Override
             public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
-                assert mNativePlatformView != 0;
-                nativeSurfaceSetSize(mNativePlatformView, width, height, density);
+                assert mViewportObserver != null;
+                mViewportObserver.onViewportMetricsChanged(width, height, density);
             }
 
             @Override
@@ -69,10 +80,45 @@ public class PlatformView extends SurfaceView {
         }
     }
 
-    private static native long nativeAttach();
+    private int getTypeForAction(int maskedAction) {
+        if (maskedAction == MotionEvent.ACTION_DOWN)
+            return EventType.POINTER_DOWN;
+        if (maskedAction == MotionEvent.ACTION_UP)
+            return EventType.POINTER_UP;
+        if (maskedAction == MotionEvent.ACTION_MOVE)
+            return EventType.POINTER_MOVE;
+        if (maskedAction == MotionEvent.ACTION_CANCEL)
+            return EventType.POINTER_CANCEL;
+        return EventType.UNKNOWN;
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        PointerData pointerData = new PointerData();
+        pointerData.pointer = event.getPointerId(0);
+        pointerData.kind = PointerKind.TOUCH;
+        pointerData.x = event.getX();
+        pointerData.y = event.getY();
+
+        InputEvent inputEvent = new InputEvent();
+        inputEvent.type = getTypeForAction(event.getActionMasked());
+        inputEvent.timeStamp = event.getEventTime();
+        inputEvent.pointerData = pointerData;
+
+        mViewportObserver.onInputEvent(inputEvent);
+        return true;
+    }
+
+    private void attach() {
+        Core core = CoreImpl.getInstance();
+        Pair<ViewportObserver.Proxy, InterfaceRequest<ViewportObserver>> result =
+                ViewportObserver.MANAGER.getInterfaceRequest(core);
+        mViewportObserver = result.first;
+        mNativePlatformView = nativeAttach(result.second.passHandle().releaseNativeHandle());
+    }
+
+    private static native long nativeAttach(int inputObserverHandle);
     private static native void nativeDetach(long nativePlatformView);
     private static native void nativeSurfaceCreated(long nativePlatformView, Surface surface);
     private static native void nativeSurfaceDestroyed(long nativePlatformView);
-    private static native void nativeSurfaceSetSize(
-            long nativePlatformView, int width, int height, float density);
 }