Allow ForwardingDelegate to have a null delegate

ui/display/manager/forwarding_display_delegate.cc

Index: ui/display/manager/forwarding_display_delegate.cc
diff --git a/ui/display/manager/forwarding_display_delegate.cc b/ui/display/manager/forwarding_display_delegate.cc
index 0a0813da8cab588c8d5d20957927bf6d4123447e..bab0e798ab5b901396894fded843b3bff7c1fb0f 100644
--- a/ui/display/manager/forwarding_display_delegate.cc
+++ b/ui/display/manager/forwarding_display_delegate.cc
@@ -18,7 +18,8 @@ ForwardingDisplayDelegate::ForwardingDisplayDelegate(
 ForwardingDisplayDelegate::~ForwardingDisplayDelegate() {}
 
 void ForwardingDisplayDelegate::Initialize() {
-  delegate_->Initialize(binding_.CreateInterfacePtrAndBind());
+  if (delegate_)
+    delegate_->Initialize(binding_.CreateInterfacePtrAndBind());
 }
 
 void ForwardingDisplayDelegate::GrabServer() {}
@@ -27,12 +28,14 @@ void ForwardingDisplayDelegate::UngrabServer() {}
 
 void ForwardingDisplayDelegate::TakeDisplayControl(
     const DisplayControlCallback& callback) {
-  delegate_->TakeDisplayControl(callback);
+  if (delegate_)
+    delegate_->TakeDisplayControl(callback);
 }
 
 void ForwardingDisplayDelegate::RelinquishDisplayControl(
     const DisplayControlCallback& callback) {
-  delegate_->TakeDisplayControl(callback);
+  if (delegate_)
+    delegate_->TakeDisplayControl(callback);
 }
 
 void ForwardingDisplayDelegate::SyncWithServer() {}
@@ -43,9 +46,11 @@ void ForwardingDisplayDelegate::ForceDPMSOn() {}
 
 void ForwardingDisplayDelegate::GetDisplays(
     const GetDisplaysCallback& callback) {
-  delegate_->GetDisplays(
-      base::Bind(&ForwardingDisplayDelegate::StoreAndForwardDisplays,
-                 base::Unretained(this), callback));
+  if (delegate_) {
+    delegate_->GetDisplays(
+        base::Bind(&ForwardingDisplayDelegate::StoreAndForwardDisplays,
+                   base::Unretained(this), callback));
+  }
 }
 
 void ForwardingDisplayDelegate::AddMode(const DisplaySnapshot& snapshot,
@@ -55,7 +60,9 @@ void ForwardingDisplayDelegate::Configure(const DisplaySnapshot& snapshot,
                                           const DisplayMode* mode,
                                           const gfx::Point& origin,
                                           const ConfigureCallback& callback) {
-  delegate_->Configure(snapshot.display_id(), mode->Clone(), origin, callback);
+  if (delegate_)
+    delegate_->Configure(snapshot.display_id(), mode->Clone(), origin,
+                         callback);
 }
 
 void ForwardingDisplayDelegate::CreateFrameBuffer(const gfx::Size& size) {}
@@ -63,14 +70,16 @@ void ForwardingDisplayDelegate::CreateFrameBuffer(const gfx::Size& size) {}
 void ForwardingDisplayDelegate::GetHDCPState(
     const DisplaySnapshot& snapshot,
     const GetHDCPStateCallback& callback) {
-  delegate_->GetHDCPState(snapshot.display_id(), callback);
+  if (delegate_)
+    delegate_->GetHDCPState(snapshot.display_id(), callback);
 }
 
 void ForwardingDisplayDelegate::SetHDCPState(
     const DisplaySnapshot& snapshot,
     HDCPState state,
     const SetHDCPStateCallback& callback) {
-  delegate_->SetHDCPState(snapshot.display_id(), state, callback);
+  if (delegate_)
+    delegate_->SetHDCPState(snapshot.display_id(), state, callback);
 }
 
 std::vector<ColorCalibrationProfile>
@@ -90,8 +99,10 @@ bool ForwardingDisplayDelegate::SetColorCorrection(
     const std::vector<GammaRampRGBEntry>& degamma_lut,
     const std::vector<GammaRampRGBEntry>& gamma_lut,
     const std::vector<float>& correction_matrix) {
-  delegate_->SetColorCorrection(output.display_id(), degamma_lut, gamma_lut,
-                                correction_matrix);
+  if (delegate_) {
+    delegate_->SetColorCorrection(output.display_id(), degamma_lut, gamma_lut,
+                                  correction_matrix);
+  }
   // DrmNativeDisplayDelegate always returns true so this will too.
   return true;
 }