Add EventForwarder for routing touch events

content/public/android/java/src/org/chromium/content_public/browser/EventForwarder.java

Index: content/public/android/java/src/org/chromium/content_public/browser/EventForwarder.java
diff --git a/content/public/android/java/src/org/chromium/content_public/browser/EventForwarder.java b/content/public/android/java/src/org/chromium/content_public/browser/EventForwarder.java
new file mode 100644
index 0000000000000000000000000000000000000000..a727bca6b680898887265a2b453a49b6d4947336
--- /dev/null
+++ b/content/public/android/java/src/org/chromium/content_public/browser/EventForwarder.java
@@ -0,0 +1,34 @@
+// 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.content_public.browser;
+
+import android.view.MotionEvent;
+
+/**
+ * Public interface which defines the methods used to forward input/view events
+ * to native. Call {@link WebContents#getEventForwarder()} to get the instance
+ * implemented for the associated {@link WebContents} internally.
+ */
+public interface EventForwarder {
+    /**
+     * Sets the current amount to offset incoming touch events by (including MotionEvent and
+     * DragEvent). This is used to handle content moving and not lining up properly with the
+     * android input system.
+     * @param dx The X offset in pixels to shift touch events.
+     * @param dy The Y offset in pixels to shift touch events.
+     */
+    void setCurrentTouchEventOffsets(float dx, float dy);
+
+    /**
+     * @see {@link android.view.View.onTouchEvent(MotionEvent)
+     */
+    boolean onTouchEvent(MotionEvent event);
+
+    /**
+     * Called by PopupWindow-based touch handles.
+     * @param event the MotionEvent targeting the handle.
+     */
+    boolean onTouchHandleEvent(MotionEvent event);
+}