Add support for Android spellcheck menu in Chrome/WebViews

base/android/java/src/org/chromium/base/ApiCompatibilityUtils.java

Index: base/android/java/src/org/chromium/base/ApiCompatibilityUtils.java
diff --git a/base/android/java/src/org/chromium/base/ApiCompatibilityUtils.java b/base/android/java/src/org/chromium/base/ApiCompatibilityUtils.java
index 24f85d6635fce1bcd806aff172a7d6afb4535de8..2e74589cabbc9c6ecc4bf42a75ca9904d25f5257 100644
--- a/base/android/java/src/org/chromium/base/ApiCompatibilityUtils.java
+++ b/base/android/java/src/org/chromium/base/ApiCompatibilityUtils.java
@@ -671,6 +671,17 @@ public class ApiCompatibilityUtils {
         }
     }
 
+    /**
+     * @param activity The {@link Activity} to check.
+     * @return Whether or not {@code activity} is currently in Android N+ multi-window mode.
+     */
+    public static boolean isInMultiWindowMode(Activity activity) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
+            return false;
+        }
+        return activity.isInMultiWindowMode();
+    }
+
     /**
      *  Null-safe equivalent of {@code a.equals(b)}.
      *