Pointer watcher modifications to support laser pointer.

ash/shell/shell_delegate_impl.cc

Index: ash/shell/shell_delegate_impl.cc
diff --git a/ash/shell/shell_delegate_impl.cc b/ash/shell/shell_delegate_impl.cc
index efea66b7c75610d82abd09e3d6fa8b5b0f166c56..03d4fc16cee9a52304ce13881285a48d436ea259 100644
--- a/ash/shell/shell_delegate_impl.cc
+++ b/ash/shell/shell_delegate_impl.cc
@@ -85,6 +85,10 @@ class PaletteDelegateImpl : public PaletteDelegate {
   PaletteDelegateImpl() {};
   ~PaletteDelegateImpl() override {};
 
+  void OnLaserModeEnabled() override {}
+
+  void OnLaserModeDisabled() override {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(PaletteDelegateImpl);
 };