Adds dart fixes for Color opacity functions (flutter#154953)

fixes flutter#154572

Author: gaaclarke

packages/flutter/lib/fix_data/fix_painting.yaml

@@ -117,4 +117,36 @@ transforms:
       - kind: 'rename'
         newName: 'fromViewPadding'
 
+  - title: "Rename from 'opacity' to 'a'"
+    date: 2024-09-10
+    element:
+      uris: [ 'painting.dart' ]
+      method: 'opacity'
+      inClass: 'Color'
+    changes:
+      - kind: 'rename'
+        newName: 'a'
+
+  - title: "Rename 'withOpacity'"
+    date: 2024-09-10
+    element:
+      uris: [ 'painting.dart' ]
+      method: 'withOpacity'
+      inClass: 'Color'
+    changes:
+      - kind: 'rename'
+        newName: 'withValues'
+      - kind: 'removeParameter'
+        index: 0
+      - kind: 'addParameter'
+        index: 0
+        name: 'alpha'
+        style: optional_named
+        argumentValue:
+          expression: '{% opacity %}'
+          requiredIf: "opacity != ''"
+    variables:
+      opacity:
+        kind: 'fragment'
+        value: 'arguments[0]'
 # Before adding a new fix: read instructions at the top of this file.

packages/flutter/test_fixes/painting/painting.dart

@@ -18,4 +18,8 @@ void main() {
 
   TextPainter.computeWidth(textScaleFactor: textScaleFactor);
   TextPainter.computeMaxIntrinsicWidth(textScaleFactor: textScaleFactor);
+
+  Color color = Color.from(alpha: 1, red: 0, green: 1, blue: 0);
+  print(color.opacity);
+  color = color.withOpacity(0.55);
 }

packages/flutter/test_fixes/painting/painting.dart.expect

@@ -18,4 +18,8 @@ void main() {
 
   TextPainter.computeWidth(textScaler: TextScaler.linear(textScaleFactor));
   TextPainter.computeMaxIntrinsicWidth(textScaler: TextScaler.linear(textScaleFactor));
+
+  Color color = Color.from(alpha: 1, red: 0, green: 1, blue: 0);
+  print(color.a);
+  color = color.withValues(alpha: 0.55);
 }