[android] manage backendscope in renderer frontend

platform/android/src/android_renderer_frontend.cpp

@@ -1,6 +1,7 @@
 #include "android_renderer_frontend.hpp"
 
 #include <mbgl/map/view.hpp>
+#include <mbgl/renderer/backend_scope.hpp>
 #include <mbgl/renderer/renderer.hpp>
 
 namespace mbgl {
@@ -8,8 +9,10 @@ namespace android {
 
 AndroidRendererFrontend::AndroidRendererFrontend(
         std::unique_ptr<Renderer> renderer_,
+        RendererBackend& backend_,
         InvalidateCallback invalidate)
         : renderer(std::move(renderer_))
+        , backend(backend_)
         , asyncInvalidate([=, invalidate=std::move(invalidate)]() {
             invalidate();
         }) {
@@ -38,6 +41,8 @@ void AndroidRendererFrontend::render(View& view) {
     assert (renderer);
     if (!updateParameters) return;
 
+    BackendScope guard { backend };
+
     renderer->render(view, *updateParameters);
 }
 

platform/android/src/android_renderer_frontend.hpp

@@ -2,6 +2,7 @@
 #pragma once
 
 #include <mbgl/annotation/annotation.hpp>
+#include <mbgl/renderer/renderer_backend.hpp>
 #include <mbgl/renderer/renderer_frontend.hpp>
 #include <mbgl/util/async_task.hpp>
 #include <mbgl/util/geo.hpp>
@@ -23,7 +24,7 @@ namespace android {
 class AndroidRendererFrontend : public RendererFrontend {
 public:
     using InvalidateCallback = std::function<void ()>;
-    AndroidRendererFrontend(std::unique_ptr<Renderer>, InvalidateCallback);
+    AndroidRendererFrontend(std::unique_ptr<Renderer>, RendererBackend&, InvalidateCallback);
     ~AndroidRendererFrontend() override;
 
     void reset() override;
@@ -43,6 +44,7 @@ public:
 
 private:
     std::unique_ptr<Renderer> renderer;
+    RendererBackend& backend;
     std::shared_ptr<UpdateParameters> updateParameters;
     util::AsyncTask asyncInvalidate;
 };

platform/android/src/native_map_view.cpp

@@ -78,6 +78,7 @@ NativeMapView::NativeMapView(jni::JNIEnv& _env,
 
     // Create a renderer frontend
     rendererFrontend = std::make_unique<AndroidRendererFrontend>(std::move(renderer),
+                                                                 *this,
                                                                  [this] { this->invalidate(); });
 
     // Create the core map