Revert "Framework wide color" (#54728)

Reverts #54415

Reverting for failures in the engine roll: https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8738846858081700577/+/u/run_test.dart_for_customer_testing_shard_and_subshard_None/stdout

lib/gpu/lib/src/render_pass.dart

@@ -95,15 +95,6 @@ base class RenderTarget {
   final DepthStencilAttachment? depthStencilAttachment;
 }
 
-// TODO(gaaclarke): Refactor this to support wide gamut colors.
-int _colorToInt(ui.Color color) {
-  assert(color.colorSpace == ui.ColorSpace.sRGB);
-  return ((color.a * 255.0).round() << 24) |
-      ((color.r * 255.0).round() << 16) |
-      ((color.g * 255.0).round() << 8) |
-      ((color.b * 255.0).round() << 0);
-}
-
 base class RenderPass extends NativeFieldWrapperClass1 {
   /// Creates a new RenderPass.
   RenderPass._(CommandBuffer commandBuffer, RenderTarget renderTarget) {
@@ -114,7 +105,7 @@ base class RenderPass extends NativeFieldWrapperClass1 {
           index,
           color.loadAction.index,
           color.storeAction.index,
-          _colorToInt(color.clearValue),
+          color.clearValue.value,
           color.texture,
           color.resolveTexture);
       if (error != null) {

lib/ui/lerp.dart

@@ -26,7 +26,7 @@ double? lerpDouble(num? a, num? b, double t) {
 ///
 /// Same as [lerpDouble] but specialized for non-null `double` type.
 double _lerpDouble(double a, double b, double t) {
-  return a + (b - a) * t;
+  return a * (1.0 - t) + b * t;
 }
 
 /// Linearly interpolate between two integers.