Support setting mouse cursor icon in Android N.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/widget/FadingBackgroundView.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/widget/FadingBackgroundView.java b/chrome/android/java/src/org/chromium/chrome/browser/widget/FadingBackgroundView.java
index a65240b57bf636cfd12cb3f2da2e1f536c90982c..4d98e4d19f726f6a48364795db825afcd425d047 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/widget/FadingBackgroundView.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/widget/FadingBackgroundView.java
@@ -9,6 +9,7 @@ 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;
@@ -98,7 +99,11 @@ public class FadingBackgroundView extends View implements View.OnClickListener {
 
     @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);
     }
 
@@ -164,6 +169,18 @@ public class FadingBackgroundView extends View implements View.OnClickListener {
         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.