Add FakeDisplayDelegate for off device usage.

ui/display/chromeos/test/test_native_display_delegate.cc

Index: ui/display/chromeos/test/test_native_display_delegate.cc
diff --git a/ui/display/chromeos/test/test_native_display_delegate.cc b/ui/display/chromeos/test/test_native_display_delegate.cc
index 2b011f003e403ff6722294f131cf2ab9d53f9d1b..23a9e013edb0ca79856a0022bfde71a7c90d67a9 100644
--- a/ui/display/chromeos/test/test_native_display_delegate.cc
+++ b/ui/display/chromeos/test/test_native_display_delegate.cc
@@ -106,8 +106,8 @@ void TestNativeDisplayDelegate::Configure(const DisplaySnapshot& output,
 
 void TestNativeDisplayDelegate::CreateFrameBuffer(const gfx::Size& size) {
   log_->AppendAction(
-      GetFramebufferAction(size, outputs_.size() >= 1 ? outputs_[0] : NULL,
-                           outputs_.size() >= 2 ? outputs_[1] : NULL));
+      GetFramebufferAction(size, outputs_.size() >= 1 ? outputs_[0] : nullptr,
+                           outputs_.size() >= 2 ? outputs_[1] : nullptr));
 }
 
 void TestNativeDisplayDelegate::GetHDCPState(
@@ -153,5 +153,10 @@ void TestNativeDisplayDelegate::RemoveObserver(
     NativeDisplayObserver* observer) {
 }
 
+display::FakeDisplayController*
+TestNativeDisplayDelegate::GetFakeDisplayController() {
+  return nullptr;
+}
+
 }  // namespace test
 }  // namespace ui