Emulate Android joystick scroll with synthetic mouse wheel event

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index 952f300d2e701811e9d720a2d1a3bea586a45b42..15c6e45584aef470c2ccc04c9533d8e3e6d1312b 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -453,7 +453,7 @@ public class ContentViewCore implements AccessibilityStateChangeListener, Displa
         mContext = context;
         mProductVersion = productVersion;
         mRenderCoordinates = new RenderCoordinates();
-        mJoystickScrollProvider = new JoystickScrollProvider(this);
+        mJoystickScrollProvider = new JoystickScrollProvider();
         mAccessibilityManager = (AccessibilityManager)
                 getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
         mSystemCaptioningBridge = CaptioningBridgeFactory.getSystemCaptioningBridge(mContext);
@@ -630,10 +630,13 @@ public class ContentViewCore implements AccessibilityStateChangeListener, Displa
 
         mZoomControlsDelegate = NO_OP_ZOOM_CONTROLS_DELEGATE;
 
+        mJoystickScrollProvider.initialize(webContents, getContainerView());
+
         final float dipScale = windowAndroid.getDisplay().getDipScale();
 
         mRenderCoordinates.reset();
         mRenderCoordinates.setDeviceScaleFactor(dipScale, windowAndroid.getContext());
+        mJoystickScrollProvider.setDeviceScaleFactor(dipScale, windowAndroid.getContext());
 
         mNativeContentViewCore = nativeInit(webContents, mViewAndroidDelegate, windowNativePointer,
                 dipScale, mRetainedJavaScriptObjects);
@@ -2872,6 +2875,7 @@ public class ContentViewCore implements AccessibilityStateChangeListener, Displa
         if (windowAndroid == null || mNativeContentViewCore == 0) return;
 
         mRenderCoordinates.setDeviceScaleFactor(dipScale, getWindowAndroid().getContext());
+        mJoystickScrollProvider.setDeviceScaleFactor(dipScale, getWindowAndroid().getContext());
         nativeSetDIPScale(mNativeContentViewCore, dipScale);
     }