Refactor ViewPropsMapBuffer -> general MapBuffer props mechanism

Summary:
Previously, ViewPropsMapBuffer conversions were hardcoded deep in Android infrastructrue. I've generalized this into a different mechanism to allow any Props struct to support MapBuffer props.

There are still some things that need to be cleaned up and this should be treated as experimental. One thing we likely want to do is remove the hardcoded IDs (fine for codegen'd code; less so for handwritten) and use compile-time-hashed IDs instead with human-readable string names.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D38708719

fbshipit-source-id: 64603dee7f21828be31346c555d99862dab304ea

Author: rshest

ReactAndroid/src/main/java/com/facebook/react/views/view/ReactMapBufferPropSetter.kt

@@ -62,6 +62,8 @@ object ReactMapBufferPropSetter {
   private const val VP_POINTER_OUT_CAPTURE = 42
   private const val VP_POINTER_OVER = 43
   private const val VP_POINTER_OVER_CAPTURE = 44
+  private const val VP_BORDER_CURVES = 45 // iOS only
+  private const val VP_FG_COLOR = 46 // iOS only?
 
   // Yoga values
   private const val YG_BORDER_WIDTH = 100
@@ -141,14 +143,20 @@ object ReactMapBufferPropSetter {
           // TODO: color for some reason can be object in Java but not in C++
           viewManager.backgroundColor(view, entry.intValue)
         }
+        VP_FG_COLOR -> {
+          // Prop not used on Android?
+        }
         VP_BORDER_COLOR -> {
           viewManager.borderColor(view, entry.mapBufferValue)
         }
         VP_BORDER_RADII -> {
           viewManager.borderRadius(view, entry.mapBufferValue)
         }
         VP_BORDER_STYLE -> {
-          viewManager.borderStyle(view, entry.intValue)
+          val styleBuffer = entry.mapBufferValue
+          if (styleBuffer.contains(CORNER_ALL)) {
+            viewManager.borderStyle(view, (styleBuffer.getDouble(CORNER_ALL)).toInt())
+          }
         }
         VP_ELEVATION -> {
           viewManager.setElevation(view, entry.doubleValue.toFloat())

ReactAndroid/src/main/jni/react/fabric/FabricMountingManager.cpp

@@ -9,7 +9,6 @@
 #include "CppViewMutationsWrapper.h"
 #include "EventEmitterWrapper.h"
 #include "StateWrapperImpl.h"
-#include "viewPropConversions.h"
 
 #include <react/jni/ReadableNativeMap.h>
 #include <react/renderer/components/scrollview/ScrollViewProps.h>
@@ -264,12 +263,11 @@ local_ref<jobject> FabricMountingManager::getProps(
     react_native_assert(
         newShadowView.props->rawProps.empty() &&
         "Raw props must be empty when views are using mapbuffer");
-    auto oldProps = oldShadowView.props != nullptr
-        ? static_cast<ViewProps const &>(*oldShadowView.props)
-        : ViewProps{};
-    auto newProps = static_cast<ViewProps const &>(*newShadowView.props);
-    return JReadableMapBuffer::createWithContents(
-        viewPropsDiff(oldProps, newProps));
+
+    // MapBufferBuilder must be constructed and live in this scope,
+    MapBufferBuilder builder;
+    newShadowView.props->propsDiffMapBuffer(&*oldShadowView.props, builder);
+    return JReadableMapBuffer::createWithContents(builder.build());
   } else {
     return ReadableNativeMap::newObjectCxxArgs(newShadowView.props->rawProps);
   }