Bug 1552608 - Factor out a helper CompositorBridgeParent::SetFixedLayerMargins(). r=tnikkel

Differential Revision: https://phabricator.services.mozilla.com/D48370

--HG--
extra : moz-landing-system : lando

gfx/layers/ipc/CompositorBridgeParent.cpp

@@ -1436,6 +1436,16 @@ void CompositorBridgeParent::SetConfirmedTargetAPZC(
   mApzUpdater->RunOnControllerThread(selector, task.forget());
 }
 
+void CompositorBridgeParent::SetFixedLayerMargins(ScreenIntCoord aTop,
+                                                  ScreenIntCoord aBottom) {
+  if (AsyncCompositionManager* manager = GetCompositionManager(nullptr)) {
+    manager->SetFixedLayerMargins(aTop, aBottom);
+  }
+
+  Invalidate();
+  ScheduleComposition();
+}
+
 void CompositorBridgeParent::InitializeLayerManager(
     const nsTArray<LayersBackend>& aBackendHints) {
   NS_ASSERTION(!mLayerManager, "Already initialised mLayerManager");

gfx/layers/ipc/CompositorBridgeParent.h

@@ -394,6 +394,7 @@ class CompositorBridgeParent final : public CompositorBridgeParentBase,
       LayerTransactionParent* aLayerTree) override {
     return mCompositionManager;
   }
+  void SetFixedLayerMargins(ScreenIntCoord aTop, ScreenIntCoord aBottom);
 
   PTextureParent* AllocPTextureParent(
       const SurfaceDescriptor& aSharedData, const ReadLockDescriptor& aReadLock,

gfx/layers/ipc/UiCompositorControllerParent.cpp

@@ -119,13 +119,7 @@ mozilla::ipc::IPCResult UiCompositorControllerParent::RecvFixedBottomOffset(
       CompositorBridgeParent::GetCompositorBridgeParentFromLayersId(
           mRootLayerTreeId);
   if (parent) {
-    AsyncCompositionManager* manager = parent->GetCompositionManager(nullptr);
-    if (manager) {
-      manager->SetFixedLayerMargins(0, aOffset);
-    }
-
-    parent->Invalidate();
-    parent->ScheduleComposition();
+    parent->SetFixedLayerMargins(0, aOffset);
   }
 #endif  // defined(MOZ_WIDGET_ANDROID)