Don't use drag to corner resizing for unresizable windows

ash/wm/window_util.cc

Index: ash/wm/window_util.cc
diff --git a/ash/wm/window_util.cc b/ash/wm/window_util.cc
index b0921b892bbfc93669efbc1038dc342dff86119f..e3ce3fb11982e62b9e450c7763b8cfa91e3e3a99 100644
--- a/ash/wm/window_util.cc
+++ b/ash/wm/window_util.cc
@@ -79,6 +79,10 @@ bool CanMaximizeWindow(const aura::Window* window) {
   return window->GetProperty(aura::client::kCanMaximizeKey);
 }
 
+bool CanResizeWindow(const aura::Window* window) {
+  return window->GetProperty(aura::client::kCanResizeKey);
+}
+
 bool IsWindowNormal(const aura::Window* window) {
   return IsWindowStateNormal(window->GetProperty(aura::client::kShowStateKey));
 }