Relands: Telemetry: hooks "chrome.gpuBenchmarking.smoothScrollBy" with java on android.

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

Index: content/public/android/java/src/org/chromium/content/browser/SmoothScroller.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/SmoothScroller.java b/content/public/android/java/src/org/chromium/content/browser/SmoothScroller.java
new file mode 100644
index 0000000000000000000000000000000000000000..f95f82d9538d37f8767372c2988dfa3cf9dd126b
--- /dev/null
+++ b/content/public/android/java/src/org/chromium/content/browser/SmoothScroller.java
@@ -0,0 +1,137 @@
+// Copyright (c) 2012 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.browser;
+
+import android.animation.TimeAnimator;
+import android.animation.TimeAnimator.TimeListener;
+import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.SystemClock;
+import android.util.Log;
+import android.view.MotionEvent;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+/**
+ * Provides a Java-side implementation for chrome.gpuBenchmarking.smoothScrollBy.
+ */
+@JNINamespace("content")
+public class SmoothScroller {
+    private final ContentViewCore mContentViewCore;
+    private final boolean mScrollDown;
+    private final float mMouseEventX;
+    private final float mMouseEventY;
+
+    private final Handler mHandler = new Handler(Looper.getMainLooper());
+
+    private TimeAnimator mTimeAnimator;
+
+    private int mNativePtr;
+    private long mDownTime;
+    private float mCurrentY;
+
+    private final byte STATE_INITIAL = 0;
+    private final byte STATE_MOVING = 1;
+    private final byte STATE_PENDING_UP = 2;
+    private final byte STATE_FINAL = 3;
+    private byte state = STATE_INITIAL;
+
+    SmoothScroller(ContentViewCore contentViewCore, boolean scrollDown,
+            int mouseEventX, int mouseEventY) {
+        mContentViewCore = contentViewCore;
+        mScrollDown = scrollDown;
+        float scale = mContentViewCore.getScale();
+        mMouseEventX = mouseEventX * scale;
+        mMouseEventY = mouseEventY * scale;
+        mCurrentY = mMouseEventY;
+    }
+
+    @CalledByNative
+    void start(int nativePtr) {
+        assert mNativePtr == 0;
+        mNativePtr = nativePtr;
+
+        Runnable runnable = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) ?
+            createJBRunnable() : createPreJBRunnable();
+        mHandler.post(runnable);
+    }
+
+    boolean sendEvent(long time) {
+        switch (state) {
+            case STATE_INITIAL: {
+                mDownTime = SystemClock.uptimeMillis();
+                MotionEvent event = MotionEvent.obtain(mDownTime, mDownTime,
+                        MotionEvent.ACTION_DOWN, mMouseEventX, mCurrentY, 0);
+                mContentViewCore.onTouchEvent(event);
+                event.recycle();
+                state = STATE_MOVING;
+                break;
+            }
+            case STATE_MOVING: {
+                double delta = nativeGetScrollDelta(mNativePtr, mContentViewCore.getScale());
+                if (delta != 0) {
+                    mCurrentY += mScrollDown ? -delta : delta;
+
+                    MotionEvent event = MotionEvent.obtain(mDownTime, time,
+                            MotionEvent.ACTION_MOVE, mMouseEventX, mCurrentY, 0);
+                    mContentViewCore.onTouchEvent(event);
+                    event.recycle();
+                }
+                if (nativeHasFinished(mNativePtr))
+                    state = STATE_PENDING_UP;
+                break;
+            }
+            case STATE_PENDING_UP: {
+                MotionEvent event = MotionEvent.obtain(mDownTime, time,
+                        MotionEvent.ACTION_UP, mMouseEventX, mCurrentY, 0);
+                mContentViewCore.onTouchEvent(event);
+                event.recycle();
+                nativeSetHasSentMotionUp(mNativePtr);
+                state = STATE_FINAL;
+                break;
+            }
+        }
+        return state != STATE_FINAL;
+    }
+
+    private Runnable createJBRunnable() {
+        // On JB, we rely on TimeAnimator to send events tied with vsync.
+        return new Runnable() {
+            @Override
+            public void run() {
+                mTimeAnimator = new TimeAnimator();
+                mTimeAnimator.setTimeListener(new TimeListener() {
+                    @Override
+                    public void onTimeUpdate(TimeAnimator animation, long totalTime,
+                            long deltaTime) {
+                        if (!sendEvent(mDownTime + totalTime)) {
+                            mTimeAnimator.end();
+                        }
+                    }
+                });
+                mTimeAnimator.start();
+            }
+        };
+    }
+
+    private Runnable createPreJBRunnable() {
+        // Pre-JB there's no TimeAnimator, so we keep posting messages.
+        return new Runnable() {
+            @Override
+            public void run() {
+                if (sendEvent(SystemClock.uptimeMillis())) {
+                    mHandler.post(this);
+                }
+            }
+        };
+    }
+
+    private native double nativeGetScrollDelta(
+            int nativeTouchSmoothScrollGestureAndroid, double scale);
+    private native boolean nativeHasFinished(int nativeTouchSmoothScrollGestureAndroid);
+    private native void nativeSetHasSentMotionUp(int nativeTouchSmoothScrollGestureAndroid);
+}