Wires up MotionEvents for mojo_shell_apk on Android.

mojo/services/native_viewport/android/src/org/chromium/mojo/MojoViewport.java

Index: mojo/services/native_viewport/android/src/org/chromium/mojo/MojoViewport.java
diff --git a/mojo/services/native_viewport/android/src/org/chromium/mojo/MojoViewport.java b/mojo/services/native_viewport/android/src/org/chromium/mojo/MojoViewport.java
index 36d24406ad13c7d1a44aadc286b93a71058f62d2..87fd633f5ce21f10583e579998b4ac1b450683b0 100644
--- a/mojo/services/native_viewport/android/src/org/chromium/mojo/MojoViewport.java
+++ b/mojo/services/native_viewport/android/src/org/chromium/mojo/MojoViewport.java
@@ -7,6 +7,7 @@ package org.chromium.mojo;
 import android.app.Activity;
 import android.content.Context;
 import android.util.AttributeSet;
+import android.view.MotionEvent;
 import android.view.Surface;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
@@ -62,9 +63,35 @@ public class MojoViewport extends SurfaceView {
         mNativeMojoViewport = 0;
     }
 
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        return nativeMotionEvent(mNativeMojoViewport,
+                                 true,
+                                 event.getPointerId(0),
+                                 event.getAction(),
+                                 event.getX(), event.getY(),
+                                 event.getEventTime());
+    }
+
+    @Override
+    public boolean onTrackballEvent(MotionEvent event) {
+        return nativeMotionEvent(mNativeMojoViewport,
+                                false,
+                                event.getPointerId(0),
+                                event.getAction(),
+                                event.getX(), event.getY(),
+                                event.getEventTime());
+    }
+
     private static native int nativeInit(int init);
     private static native void nativeDestroy(int nativeMojoViewport);
     private static native void nativeSurfaceCreated(int nativeMojoViewport, Surface surface);
     private static native void nativeSurfaceDestroyed(int nativeMojoViewport);
     private static native void nativeSurfaceSetSize(int nativeMojoViewport, int width, int height);
+    private static native boolean nativeMotionEvent(int nativeMojoViewport,
+                                                    boolean isTouch,

[abarth-chromium, 2013/11/07 00:29:11]

Are there other possibilities?  I wonder if we should map the Java-to-native
function calls one-to-one.

+                                                    int pointerId,
+                                                    int action,
+                                                    float x, float y,
+                                                    long timeMs);
 };