Use batched buffer packing in synchronouslyUpdateProps on C++ side

Summary:
Pack animated property updates into a compact byte+double buffer format in C++ and add the corresponding Java-side buffer decoder. This avoids per-property JNI calls by batching all updates into a single cross-boundary transfer.

Gated behind the `optimizedAnimatedPropUpdates` feature flag.

Changelog:
[Android][Changed] - Pack animated prop updates from the C++ animation backend into a single byte+double buffer instead of issuing one JNI call per property (gated by `optimizedAnimatedPropUpdates`)

Differential Revision: D101157452

Author: Bartlomiej Bloniarz

packages/react-native/ReactCommon/react/renderer/animationbackend/AnimatedPropSerializer.cpp

@@ -559,7 +559,6 @@ void packBackfaceVisibility(
   }
   dyn.insert("backfaceVisibility", visibilityStr);
 }
-
 void packAnimatedProp(
     folly::dynamic& dyn,
     const std::unique_ptr<AnimatedPropBase>& animatedProp) {

packages/react-native/ReactCommon/react/renderer/animationbackend/AnimationBackend.cpp

@@ -11,7 +11,6 @@
 #include <react/debug/react_native_assert.h>
 #include <react/featureflags/ReactNativeFeatureFlags.h>
 #include <react/renderer/animationbackend/AnimatedPropsSerializer.h>
-#include <react/renderer/graphics/Color.h>
 #include <chrono>
 #include <utility>
 
@@ -85,7 +84,7 @@ void AnimationBackend::applySurfaceUpdates(
     if (updates.hasLayoutUpdates) {
       commitUpdates(surfaceId, updates);
     } else {
-      synchronouslyUpdateProps(updates.propsMap);
+      synchronouslyUpdateProps(surfaceId, updates.propsMap);
     }
   }
 
@@ -194,18 +193,28 @@ void AnimationBackend::commitUpdates(
       });
 }
 
-void AnimationBackend::synchronouslyUpdateProps(
+void AnimationBackend::synchronouslyUpdatePropsUnbuffered(
     const std::unordered_map<Tag, AnimatedProps>& updates) {
   for (auto& [tag, animatedProps] : updates) {
-    // TODO: We shouldn't repack it into dynamic, but for that a rewrite
-    // of synchronouslyUpdateViewOnUIThread is needed
     auto dyn = animationbackend::packAnimatedProps(animatedProps);
     if (auto uiManager = uiManager_.lock()) {
       uiManager->synchronouslyUpdateViewOnUIThread(tag, dyn);
     }
   }
 }
 
+void AnimationBackend::synchronouslyUpdateProps(
+    SurfaceId surfaceId,
+    const std::unordered_map<Tag, AnimatedProps>& updates) {
+  if (ReactNativeFeatureFlags::optimizedAnimatedPropUpdates()) {
+    if (auto uiManager = uiManager_.lock()) {
+      uiManager->synchronouslyUpdateAnimatedPropsOnUIThread(surfaceId, updates);
+    }
+    return;
+  }
+  synchronouslyUpdatePropsUnbuffered(updates);
+}
+
 void AnimationBackend::requestAsyncFlushForSurfaces(
     const std::set<SurfaceId>& surfaces) {
   react_native_assert(

packages/react-native/ReactCommon/react/renderer/animationbackend/AnimationBackend.h

@@ -52,7 +52,8 @@ class AnimationBackend : public UIManagerAnimationBackend {
       std::shared_ptr<AnimationChoreographer> animationChoreographer,
       std::shared_ptr<UIManager> uiManager);
   void commitUpdates(SurfaceId surfaceId, SurfaceUpdates &surfaceUpdates);
-  void synchronouslyUpdateProps(const std::unordered_map<Tag, AnimatedProps> &updates);
+  void synchronouslyUpdateProps(SurfaceId surfaceId, const std::unordered_map<Tag, AnimatedProps> &updates);
+  void synchronouslyUpdatePropsUnbuffered(const std::unordered_map<Tag, AnimatedProps> &updates);
   void requestAsyncFlushForSurfaces(const std::set<SurfaceId> &surfaces);
   void clearRegistry(SurfaceId surfaceId) override;
   void clearRegistryOnSurfaceStop(SurfaceId surfaceId) override;