Support setting mouse cursor icon in Android N.

chrome/android/java/src/org/chromium/chrome/browser/widget/FadingBackgroundView.java

 // 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.chrome.browser.widget;
 
 import android.animation.Animator;
 import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.View;
+import android.view.ViewGroup.LayoutParams;
 
 import org.chromium.base.ObserverList;
 import org.chromium.chrome.browser.util.MathUtils;
 import org.chromium.ui.interpolators.BakedBezierInterpolator;
 
 /**
  * This view is used to obscure content and bring focus to a foreground view (i.e. the Chrome Home
  * bottom sheet or the omnibox suggestions).
  *
  * If the view is disabled, then its alpha will be set to 0f and it will not receive touch events.
@@ skipping 69 matching lines @@
     @Override
     public void setAlpha(float alpha) {
         super.setAlpha(alpha);
 
         int newVisibility = alpha <= 0f ? View.GONE : View.VISIBLE;
         setVisibility(newVisibility);
     }
 
     @Override
     public void setVisibility(int visibility) {
-        if (getAlpha() <= 0f && visibility == View.VISIBLE) return;
+        if (getAlpha() <= 0f && visibility == View.VISIBLE) {
+            changeHeight(0);

[Ted C, 2017/07/18 16:41:18]

changing the layout height in this case seems wrong to me.  This seems like
where we should be setting it to gone.  I'll defer to mdjones@ though as I'm not
familiar with these changes:

Source:
https://codereview.chromium.org/2709883002

[mdjones, 2017/07/19 18:40:50]

For this view, alpha is tied to visibility (see setAlpha above). This check is
to block anyone trying to set the view to visible when the alpha is 0, i.e. the
view should already be gone at this point.

+            return;
+        }
+        changeHeight(visibility == View.VISIBLE ? LayoutParams.MATCH_PARENT : 0);
         super.setVisibility(visibility);
     }
 
     @Override
     protected void dispatchVisibilityChanged(View view, int visibility) {
         if (getAlpha() <= 0f && visibility == View.VISIBLE) return;
         super.dispatchVisibilityChanged(view, visibility);
     }
 
     @Override
@@ skipping 46 matching lines @@
         if (mOverlayAnimator == fadeAnimation && mOverlayAnimator.isRunning()) {
             return;
         } else if (mOverlayAnimator != null) {
             mOverlayAnimator.cancel();
         }
         mOverlayAnimator = fadeAnimation;
         mOverlayAnimator.start();
     }
 
     /**
+     * Change height of this view.
+     * @param height The height that it should be.
+     */
+    private void changeHeight(int height) {
+        LayoutParams params = getLayoutParams();
+        if (params != null && params.height != height) {
+            params.height = height;
+            setLayoutParams(params);
+        }
+    }
+
+    /**
      * Adds an observer to this fading view.
      * @param observer The observer to be added.
      */
     public void addObserver(FadingViewObserver observer) {
         mObservers.addObserver(observer);
     }
 
     @Override
     public void onClick(View view) {
         for (FadingViewObserver o : mObservers) o.onFadingViewClick();
     }
 }