Bug 1442627 - Reduce exposure of the APZCTreeManager. r=botond

Callers should be using one of the more specific subinterfaces like
IAPZCTreeManager (for controller-API methods) or APZSampler (for
sampler-API methods). There's also a bunch of android-specific
dynamic toolbar code that uses this function - I don't want to
deal with that right now, so instead of removing it entirely we can just
make it Android-only.

MozReview-Commit-ID: I8DYWLYoFgP

--HG--
extra : rebase_source : 75e05825194f9c6843506bb5d82e1a0c6e2b08bb

gfx/layers/ipc/CompositorBridgeParent.cpp

@@ -1185,11 +1185,13 @@ CompositorBridgeParent::DeallocPAPZParent(PAPZParent* aActor)
   return true;
 }
 
+#if defined(MOZ_WIDGET_ANDROID)
 RefPtr<APZCTreeManager>
 CompositorBridgeParent::GetAPZCTreeManager()
 {
   return mApzcTreeManager;
 }
+#endif
 
 RefPtr<APZSampler>
 CompositorBridgeParent::GetAPZSampler()

gfx/layers/ipc/CompositorBridgeParent.h

@@ -464,7 +464,9 @@ public:
   PAPZParent* AllocPAPZParent(const uint64_t& aLayersId) override;
   bool DeallocPAPZParent(PAPZParent* aActor) override;
 
+#if defined(MOZ_WIDGET_ANDROID)
   RefPtr<APZCTreeManager> GetAPZCTreeManager();
+#endif
   RefPtr<APZSampler> GetAPZSampler();
 
   CompositorOptions GetOptions() const {