Remove redundant field initialization in Java code.

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/Stack.java

 // Copyright 2015 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.chrome.browser.compositor.layouts.phone.stack;
 
 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.content.Context;
 import android.content.res.Resources;
@@ skipping 170 matching lines @@
     private float mMaxOverScrollSlide;
     private final Interpolator mOverScrollAngleInterpolator =
             new AccelerateDecelerateInterpolator();
     private final Interpolator mUnderScrollAngleInterpolator =
             ChromeAnimation.getDecelerateInterpolator();
     private final Interpolator mOverscrollSlideInterpolator =
             new AccelerateDecelerateInterpolator();
 
     // Drag Lock
     private DragLock mDragLock = DragLock.NONE;
-    private long mLastScrollUpdate = 0;
-    private float mMinScrollMotion = 0;
+    private long mLastScrollUpdate;
+    private float mMinScrollMotion;
 
     // Scrolling Variables
-    private float mScrollTarget = 0;
-    private float mScrollOffset = 0;
-    private float mScrollOffsetForDyingTabs = 0;
-    private float mCurrentScrollDirection = 0.0f;
-    private StackTab mScrollingTab = null;
+    private float mScrollTarget;
+    private float mScrollOffset;
+    private float mScrollOffsetForDyingTabs;
+    private float mCurrentScrollDirection;
+    private StackTab mScrollingTab;
 
     // Swipe Variables
     private float mSwipeUnboundScrollOffset;
     private float mSwipeBoundedScrollOffset;
     private boolean mSwipeIsCancelable;
     private boolean mSwipeCanScroll;
     private boolean mInSwipe;
 
     // Discard
     private StackTab mDiscardingTab;
@@ skipping 2333 matching lines @@
     public void swipeFlingOccurred(
             long time, float x, float y, float tx, float ty, float vx, float vy) {
         if (!mInSwipe) return;
 
         // Propagate the fling data.
         fling(time, x, y, vx, vy);
 
         onUpOrCancel(time);
     }
 }