gfx::Screen: Replace GetWindowUnderCursor() with IsWindowUnderCursor().

ui/gfx/screen_android.cc

Index: ui/gfx/screen_android.cc
diff --git a/ui/gfx/screen_android.cc b/ui/gfx/screen_android.cc
index 41099f18b99eeaa768a69d63435cd63d9188e012..eb36444fa8d4dc722b87d6fbc3083d372647ddb9 100644
--- a/ui/gfx/screen_android.cc
+++ b/ui/gfx/screen_android.cc
@@ -18,9 +18,9 @@ class ScreenAndroid : public Screen {
 
   gfx::Point GetCursorScreenPoint() override { return gfx::Point(); }
 
-  gfx::NativeWindow GetWindowUnderCursor() override {
+  bool IsWindowUnderCursor(gfx::NativeWindow window) override {
     NOTIMPLEMENTED();
-    return NULL;
+    return false;
   }
 
   gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) override {