Support setting mouse cursor icon in Android N.

chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java

 // Copyright 2014 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.fullscreen;
 
 import android.app.Activity;
 import android.content.res.Resources;
+import android.os.Build;
 import android.view.Gravity;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
 import android.view.Window;
 import android.widget.FrameLayout;
 
 import org.chromium.base.ActivityState;
 import org.chromium.base.ApplicationStatus;
@@ skipping 498 matching lines @@
             }
 
             // Whether we need the compositor to draw again to update our animation.
             // Should be |false| when the browser controls are only moved through the page
             // scrolling.
             boolean needsAnimate = shouldShowAndroidControls();
             for (int i = 0; i < mListeners.size(); i++) {
                 mListeners.get(i).onControlsOffsetChanged(
                         getTopControlOffset(), getBottomControlOffset(), needsAnimate);
             }
+
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {

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

why is this needed?  this is while the top controls are scrolling off right? 
The view is made to be gone in that case, so do we still need this?

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

The view is still present at its location (i.e., the visibility is not gone)
though it is not visible. So the wrong icons (such as text I-beam) will be shown
without this code.

[Ted C, 2017/07/21 18:45:31]

Since the controlcontainer is a child of the coordinatorlayout, why doesn't your
visibility check handle this?

It is INVISIBLE which should have it skipped.

[jaebaek, 2017/07/24 07:34:11]

You are right. I dropped this code.

+                if (offset != 0.0f && mPreviousControlOffset == 0.0f) {
+                    mControlContainer.getView().setPointerIcon(null);
+                }
+            }
         }
 
         final Tab tab = getTab();
         if (tab != null && areBrowserControlsOffScreen() && mIsEnteringPersistentModeState) {
             getHtmlApiHandler().enterFullscreen(tab);
             mIsEnteringPersistentModeState = false;
         }
 
         updateContentViewChildrenState();
 
@@ skipping 131 matching lines @@
             updateVisuals();
         }
     }
 
     @Override
     public void onContentViewScrollingStateChanged(boolean scrolling) {
         mContentViewScrolling = scrolling;
         if (!scrolling) updateVisuals();
     }
 }