Add in gesture for immersive mode

ash/root_window_controller.cc

Index: ash/root_window_controller.cc
diff --git a/ash/root_window_controller.cc b/ash/root_window_controller.cc
index 3af8f489002c05f1b530354e6ab9b435037b7505..2d4461a81825873f171e971ce327800cf29b9d2f 100644
--- a/ash/root_window_controller.cc
+++ b/ash/root_window_controller.cc
@@ -491,6 +491,17 @@ bool RootWindowController::IsImmersiveMode() const {
   return false;
 }
 
+void RootWindowController::SetPendingImmersiveGesture(bool value) {
+  aura::Window* container = workspace_controller_->GetActiveWorkspaceWindow();
+  for (size_t i = 0; i < container->children().size(); ++i) {
+    aura::Window* child = container->children()[i];
+    if (child->IsVisible() && child->GetProperty(kImmersiveModeKey)) {
+      child->SetProperty(kPendingImmersiveGestureKey, value);
+      return;
+    }
+  }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RootWindowController, private: