[Android] Perform eager gesture recognition on MotionEvents

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

 // Copyright 2013 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.content.Context;
 import android.util.DisplayMetrics;
 import android.view.MotionEvent;
 
 /**
  * This objects controls the scroll snapping behavior based on scroll updates.
  */
 class SnapScrollController {
     private static final String TAG = "SnapScrollController";
     private static final int SNAP_NONE = 0;
     private static final int SNAP_HORIZ = 1;
     private static final int SNAP_VERT = 2;
     private static final int SNAP_BOUND = 16;
 
     private float mChannelDistance = 16f;
     private int mSnapScrollMode = SNAP_NONE;
     private int mFirstTouchX = -1;
     private int mFirstTouchY = -1;
     private float mDistanceX = 0;
     private float mDistanceY = 0;
-    private ZoomManager mZoomManager;
 
-    SnapScrollController(Context context, ZoomManager zoomManager) {
+    SnapScrollController(Context context) {
         calculateChannelDistance(context);
-        mZoomManager = zoomManager;
     }
 
     /**
      * Updates the snap scroll mode based on the given X and Y distance to be moved on scroll.
      * If the scroll update is above a threshold, the snapping behavior is reset.
      * @param distanceX X distance for the current scroll update.
      * @param distanceY Y distance for the current scroll update.
      */
     void updateSnapScrollMode(float distanceX, float distanceY) {
         if (mSnapScrollMode == SNAP_HORIZ || mSnapScrollMode == SNAP_VERT) {
@@ skipping 14 matching lines @@
                     mDistanceY = 0;
                 }
             }
         }
     }
 
     /**
      * Sets the snap scroll mode based on the event type.
      * @param event The received MotionEvent.
      */
-    void setSnapScrollingMode(MotionEvent event) {
+    void setSnapScrollingMode(MotionEvent event, boolean isScaleGestureDetectionInProgress) {
         switch(event.getAction()) {
             case MotionEvent.ACTION_DOWN:
                 mSnapScrollMode = SNAP_NONE;
                 mFirstTouchX = (int) event.getX();
                 mFirstTouchY = (int) event.getY();
                 break;
              // Set scrolling mode to SNAP_X if scroll towards x-axis exceeds SNAP_BOUND
              // and movement towards y-axis is trivial.
              // Set scrolling mode to SNAP_Y if scroll towards y-axis exceeds SNAP_BOUND
              // and movement towards x-axis is trivial.
              // Scrolling mode will remain in SNAP_NONE for other conditions.
             case MotionEvent.ACTION_MOVE:
-                if (!mZoomManager.isScaleGestureDetectionInProgress() &&
+                if (!isScaleGestureDetectionInProgress &&
                         mSnapScrollMode == SNAP_NONE) {
                     int xDiff = (int) Math.abs(event.getX() - mFirstTouchX);
                     int yDiff = (int) Math.abs(event.getY() - mFirstTouchY);
                     if (xDiff > SNAP_BOUND && yDiff < SNAP_BOUND) {
                         mSnapScrollMode = SNAP_HORIZ;
                     } else if (xDiff < SNAP_BOUND && yDiff > SNAP_BOUND) {
                         mSnapScrollMode = SNAP_VERT;
                     }
                 }
                 break;
@@ skipping 41 matching lines @@
         return mSnapScrollMode == SNAP_HORIZ;
     }
 
     /**
      * @return Whether currently snapping scrolls.
      */
     boolean isSnappingScrolls() {
         return mSnapScrollMode != SNAP_NONE;
     }
 }