Allow platforms to provide custom IsColorMeaningful implementation (#51478)

Summary:
On windows, not all PlatformColors are convertible directly into colorComponents.  For PlatformColors, the Color.isColorMeaningful may need to do something other than check the alpha component of the color.

Here I'm moving the implementation of isColorMeaningful into the HostPlatformColor implemantion to allow the host platform to customize the implemenation of isColorMeaningful.

## Changelog:

[INTERNAL] [ADDED] - Allow platforms to override isColorMeaningful

Pull Request resolved: #51478

Test Plan: No behavior change in core. -- Will be used in react-native-windows to fix microsoft/react-native-windows#14006

Reviewed By: NickGerleman

Differential Revision: D75088378

Pulled By: javache

fbshipit-source-id: 0a456bfe6be93098e3d8fa22390a971e14a4312b

Author: acoates-ms

packages/react-native/ReactCommon/react/renderer/graphics/Color.cpp

@@ -14,7 +14,7 @@ bool isColorMeaningful(const SharedColor& color) noexcept {
     return false;
   }
 
-  return colorComponentsFromColor(color).alpha > 0;
+  return hostPlatformColorIsColorMeaningful(*color);
 }
 
 // Create Color from float RGBA values in [0, 1] range

packages/react-native/ReactCommon/react/renderer/graphics/platform/android/react/renderer/graphics/HostPlatformColor.h

@@ -56,4 +56,8 @@ inline float blueFromHostPlatformColor(Color color) {
   return static_cast<uint8_t>((color >> 0) & 0xff);
 }
 
+inline bool hostPlatformColorIsColorMeaningful(Color color) noexcept {
+  return alphaFromHostPlatformColor(color) > 0;
+}
+
 } // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/graphics/platform/cxx/react/renderer/graphics/HostPlatformColor.h

@@ -49,6 +49,10 @@ inline float blueFromHostPlatformColor(Color color) {
   return static_cast<uint8_t>((color >> 0) & 0xff);
 }
 
+inline bool hostPlatformColorIsColorMeaningful(Color color) noexcept {
+  return alphaFromHostPlatformColor(color) > 0;
+}
+
 inline ColorComponents colorComponentsFromHostPlatformColor(Color color) {
   float ratio = 255;
   return ColorComponents{

packages/react-native/ReactCommon/react/renderer/graphics/platform/ios/react/renderer/graphics/HostPlatformColor.h

@@ -104,6 +104,10 @@ inline float blueFromHostPlatformColor(Color color) {
   return color.getChannel(2) * 255;
 }
 
+inline bool hostPlatformColorIsColorMeaningful(Color color) noexcept {
+  return alphaFromHostPlatformColor(color) > 0;
+}
+
 } // namespace facebook::react
 
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