[core] Inline HeadlessBackend::{activate,deactivate,destroy}Context

HeadlessContext::destroyContext isn't even necessary; std::unique_ptr handles that automatically.

platform/default/mbgl/gl/headless_backend.cpp

@@ -18,7 +18,6 @@ HeadlessBackend::HeadlessBackend(std::shared_ptr<HeadlessDisplay> display_)
 
 HeadlessBackend::~HeadlessBackend() {
     deactivate();
-    destroyContext();
 }
 
 void HeadlessBackend::activate() {
@@ -31,7 +30,8 @@ void HeadlessBackend::activate() {
         createContext();
     }
 
-    activateContext();
+    assert(hasContext());
+    impl->activateContext();
 
     if (!extensionsLoaded) {
         gl::InitializeExtensions(initializeExtension);
@@ -40,7 +40,8 @@ void HeadlessBackend::activate() {
 }
 
 void HeadlessBackend::deactivate() {
-    deactivateContext();
+    assert(hasContext());
+    impl->deactivateContext();
     active = false;
 }
 
@@ -48,21 +49,6 @@ void HeadlessBackend::invalidate() {
     assert(false);
 }
 
-void HeadlessBackend::destroyContext() {
-    assert(hasContext());
-    impl.reset();
-}
-
-void HeadlessBackend::activateContext() {
-    assert(hasContext());
-    impl->activateContext();
-}
-
-void HeadlessBackend::deactivateContext() {
-    assert(hasContext());
-    impl->deactivateContext();
-}
-
 void HeadlessBackend::notifyMapChange(MapChange change) {
     if (mapChangeCallback) {
         mapChangeCallback(change);

platform/default/mbgl/gl/headless_backend.hpp

@@ -39,12 +39,6 @@ private:
 
     void createContext();
 
-private:
-    void destroyContext();
-
-    void activateContext();
-    void deactivateContext();
-
     std::unique_ptr<Impl> impl;
     std::shared_ptr<HeadlessDisplay> display;