Forward GenericMotionEvent to EventForwarder

ui/android/java/src/org/chromium/ui/base/EventForwarder.java

 // Copyright 2017 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.
 
 package org.chromium.ui.base;
 
 import android.annotation.TargetApi;
 import android.os.Build;
 import android.view.MotionEvent;
+import android.view.View;
 
 import org.chromium.base.TraceEvent;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
+import org.chromium.ui.input.JoystickScrollProvider;
 
 /**
  * Class used to forward view, input events down to native.
  */
 @JNINamespace("ui")
 public class EventForwarder {
     private long mNativeEventForwarder;
 
     // Offsets for the events that passes through.
     private float mCurrentTouchOffsetX;
     private float mCurrentTouchOffsetY;
 
+    // Provides smooth gamepad joystick-driven scrolling.
+    private JoystickScrollProvider mJoystickScrollProvider;
+
     @CalledByNative
     private static EventForwarder create(long nativeEventForwarder) {
         return new EventForwarder(nativeEventForwarder);
     }
 
     private EventForwarder(long nativeEventForwarder) {
         mNativeEventForwarder = nativeEventForwarder;
     }
 
     @CalledByNative
     private void destroy() {
         mNativeEventForwarder = 0;
+        mJoystickScrollProvider = null;
     }
 
     /**
      * @see View#onTouchEvent(MotionEvent)
      */
     public boolean onTouchEvent(MotionEvent event) {
         // TODO(mustaq): Should we include MotionEvent.TOOL_TYPE_STYLUS here?
         // crbug.com/592082
         if (event.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE) {
             // Mouse button info is incomplete on L and below
@@ skipping 126 matching lines @@
 
     @TargetApi(Build.VERSION_CODES.M)
     public void sendMouseEvent(long timeMs, int action, float x, float y, int pointerId,
             float pressure, float orientation, float tilt, int actionButton, int buttonState,
             int metaState, int toolType) {
         assert mNativeEventForwarder != 0;
         nativeOnMouseEvent(mNativeEventForwarder, timeMs, action, x, y, pointerId, pressure,
                 orientation, tilt, actionButton, buttonState, metaState, toolType);
     }
 
+    /**
+     * Handles motion event of type {@code SOURCE_CLASS_POINTER}.
+     *
+     * @param event {@link MotionEvent} instance.
+     * @param event scrollFactor scale factor used to convert wheel tick to pixel.
+     */
+    public boolean onPointerDeviceEvent(MotionEvent event, float scrollFactor) {
+        switch (event.getActionMasked()) {
+            case MotionEvent.ACTION_SCROLL:
+                assert mNativeEventForwarder != 0;
+
+                nativeOnMouseWheelEvent(mNativeEventForwarder, event.getEventTime(), event.getX(),
+                        event.getY(), event.getAxisValue(MotionEvent.AXIS_HSCROLL),
+                        event.getAxisValue(MotionEvent.AXIS_VSCROLL), scrollFactor);
+                return true;
+            case MotionEvent.ACTION_BUTTON_PRESS:
+            case MotionEvent.ACTION_BUTTON_RELEASE:
+                // TODO(mustaq): Should we include MotionEvent.TOOL_TYPE_STYLUS here?
+                // crbug.com/592082
+                if (event.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE) return onMouseEvent(event);
+        }
+
+        return false;
+    }
+
+    public JoystickScrollProvider createJoystickScrollProvider(

[boliu, 2017/03/27 17:44:44]

Having JoystickScrollProvider and whatnot in ui makes no sense to me. Why can't
these things just stay in content?

[Jinsuk Kim, 2017/03/27 22:42:06]

The motivation is to migrate these input events flow from CVC to EventForwarder.
Unlike simple touch events, generic motion events need to take care of a few
other stuff. One of them is joystick events. Without moving this, it seems not
possible (at least to me) to do the migration. 

Got any other idea?

[boliu, 2017/03/27 22:54:22]

afaict, the dependency (from higher to lower) is content -> JoyStick ->
ui/EventHandler. Is that correct? ie I don't see anything in ui or EventHandler
actually using any of this JoyStick code. So why is it in ui at all?

Pulling joystick stuff out of CVC is fine, but I don't see why it has to be in
ui?

[Jinsuk Kim, 2017/03/27 22:59:51]

.. wish it had been discussed in the crbug.com/703023 before, which I had
created just for that. EventForwarder has a reference to it. So it needs to be
where ui can have an access to, not in content any more.

[Jinsuk Kim, 2017/03/27 23:04:24]

May I was not clear. I meant that EventForwarder provides the path to native for
JoystickScrollProvider here. 

[boliu, 2017/03/27 23:19:17]

You can just make onMouseWheelEvent public here then?

[Jinsuk Kim, 2017/03/28 02:40:33]

Done. Moved Joystick.+Provider classes back to content/

+            View containerView, WindowAndroid windowAndroid) {
+        if (mJoystickScrollProvider != null) return mJoystickScrollProvider;
+        mJoystickScrollProvider = new JoystickScrollProvider(
+                containerView, windowAndroid, new JoystickScrollProvider.ScrollEmulator() {
+                    // Joystick scroll is translated to mouse wheel event.
+                    @Override
+                    public void scroll(long timeMillis, float dx, float dy) {
+                        assert mNativeEventForwarder != 0;
+                        nativeOnMouseWheelEvent(
+                                mNativeEventForwarder, timeMillis, 0, 0, -dx, -dy, 1.0f);
+                    }
+                });
+        return mJoystickScrollProvider;
+    }
+
     // All touch events (including flings, scrolls etc) accept coordinates in physical pixels.
     private native boolean nativeOnTouchEvent(long nativeEventForwarder, MotionEvent event,
             long timeMs, int action, int pointerCount, int historySize, int actionIndex, float x0,
             float y0, float x1, float y1, int pointerId0, int pointerId1, float touchMajor0,
             float touchMajor1, float touchMinor0, float touchMinor1, float orientation0,
             float orientation1, float tilt0, float tilt1, float rawX, float rawY,
             int androidToolType0, int androidToolType1, int androidButtonState,
             int androidMetaState, boolean isTouchHandleEvent);
     private native void nativeOnMouseEvent(long nativeEventForwarder, long timeMs, int action,
             float x, float y, int pointerId, float pressure, float orientation, float tilt,
             int changedButton, int buttonState, int metaState, int toolType);
+    private native void nativeOnMouseWheelEvent(long nativeEventForwarder, long timeMs, float x,
+            float y, float ticksX, float ticksY, float pixelsPerTick);
 }