Support setting mouse cursor icon in Android N.

chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
index 43563485ce8aa660a376cb30a09c26db219ece00..3b72c2790b072fd3322bcffe5357d440d42e69cb 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
@@ -10,6 +10,7 @@ import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.support.v4.view.ViewCompat;
@@ -20,6 +21,7 @@ import android.util.AttributeSet;
 import android.util.Pair;
 import android.view.DragEvent;
 import android.view.MotionEvent;
+import android.view.PointerIcon;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.accessibility.AccessibilityEvent;
@@ -182,6 +184,14 @@ public class CompositorViewHolder extends FrameLayout
         internalInit();
     }
 
+    @Override
+    public PointerIcon onResolvePointerIcon(MotionEvent event, int pointerIndex) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) return null;
+        ContentViewCore content = getActiveContent();

[Ted C, 2017/07/21 00:15:25]

do we also need to call isTabInteractive() here?  if you're in the tab switcher,
would this show the pointer icons as if you were still showing the tab?

[jaebaek, 2017/07/21 10:03:04]

I made sure that the default pointer icon (pointer/arrow) will be used when the
isTabInteractive returns false. So the default one will be chose when other view
covers CompositorViewHolder as in the tab switcher. That makes me think calling
isTabInteractive() is not necessary here. It would be still okay to call it
though. Feel free to let me know if you believe it would be safer to do that. 

+        if (content == null) return null;
+        return content.getContainerView().onResolvePointerIcon(event, pointerIndex);
+    }
+
     /**
      * Creates a {@link CompositorView}.
      * @param c     The Context to create this {@link CompositorView} in.