Deprecate M2 curves (#134417)

These have 1:1 replacements with a new name, introduced in
https://github.com/flutter/flutter/pull/129942

Land after https://github.com/flutter/packages/pull/4898

Part of https://github.com/flutter/flutter/issues/116525

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat

packages/flutter/lib/fix_data/fix_material/fix_material.yaml

@@ -897,9 +897,9 @@ transforms:
         oldName: 'showTrackOnHover'
         newName: 'trackVisibility'
 
-  # Changes made in https://github.com/flutter/flutter/pull/129942
+  # Changes made in https://github.com/flutter/flutter/pull/134417
   - title: "Migrate to 'Easing.legacy'"
-    date: 2023-07-04
+    date: 2023-12-12
     element:
       uris: [ 'material.dart' ]
       variable: 'standardEasing'
@@ -910,9 +910,9 @@ transforms:
           field: legacy
           inClass: Easing
 
-  # Changes made in https://github.com/flutter/flutter/pull/129942
+  # Changes made in https://github.com/flutter/flutter/pull/134417
   - title: "Migrate to 'Easing.legacyAccelerate'"
-    date: 2023-07-04
+    date: 2023-12-12
     element:
       uris: [ 'material.dart' ]
       variable: 'accelerateEasing'
@@ -923,9 +923,9 @@ transforms:
           field: legacyAccelerate
           inClass: Easing
 
-  # Changes made in https://github.com/flutter/flutter/pull/129942
+  # Changes made in https://github.com/flutter/flutter/pull/134417
   - title: "Migrate to 'Easing.legacyDecelerate'"
-    date: 2023-07-04
+    date: 2023-12-12
     element:
       uris: [ 'material.dart' ]
       variable: 'decelerateEasing'

packages/flutter/lib/src/material/curves.dart

@@ -6,9 +6,7 @@ import 'package:flutter/animation.dart';
 
 // The easing curves of the Material Library
 
-// TODO(guidezpl): deprecate the three curves below once customers (packages/plugins) are migrated
-
-/// The standard easing curve in the Material specification.
+/// The standard easing curve in the Material 2 specification.
 ///
 /// Elements that begin and end at rest use standard easing.
 /// They speed up quickly and slow down gradually, in order
@@ -16,18 +14,28 @@ import 'package:flutter/animation.dart';
 ///
 /// See also:
 /// * <https://material.io/design/motion/speed.html#easing>
+@Deprecated(
+  'Use Easing.legacy (M2) or Easing.standard (M3) instead. '
+  'This curve is updated in M3. '
+  'This feature was deprecated after v3.18.0-0.1.pre.'
+)
 const Curve standardEasing = Curves.fastOutSlowIn;
 
-/// The accelerate easing curve in the Material specification.
+/// The accelerate easing curve in the Material 2 specification.
 ///
 /// Elements exiting a screen use acceleration easing,
 /// where they start at rest and end at peak velocity.
 ///
 /// See also:
 /// * <https://material.io/design/motion/speed.html#easing>
+@Deprecated(
+  'Use Easing.legacyAccelerate (M2) or Easing.standardAccelerate (M3) instead. '
+  'This curve is updated in M3. '
+  'This feature was deprecated after v3.18.0-0.1.pre.'
+)
 const Curve accelerateEasing = Cubic(0.4, 0.0, 1.0, 1.0);
 
-/// The decelerate easing curve in the Material specification.
+/// The decelerate easing curve in the Material 2 specification.
 ///
 /// Incoming elements are animated using deceleration easing,
 /// which starts a transition at peak velocity (the fastest
@@ -35,4 +43,9 @@ const Curve accelerateEasing = Cubic(0.4, 0.0, 1.0, 1.0);
 ///
 /// See also:
 /// * <https://material.io/design/motion/speed.html#easing>
+@Deprecated(
+  'Use Easing.legacyDecelerate (M2) or Easing.standardDecelerate (M3) instead. '
+  'This curve is updated in M3. '
+  'This feature was deprecated after v3.18.0-0.1.pre.'
+)
 const Curve decelerateEasing = Cubic(0.0, 0.0, 0.2, 1.0);

packages/flutter/test_fixes/material/material.dart

@@ -318,11 +318,10 @@ void main() {
   );
   final Clip clip = details.clipBehavior;
 
-  // Changes made in https://github.com/flutter/flutter/pull/129942
-  // TODO(guidezpl): enable fix after https://github.com/dart-lang/sdk/issues/52902
-  // const Curve curve = standardEasing; expect Easing.legacy
-  // const Curve curve = accelerateEasing; expect Easing.legacyAccelerate
-  // const Curve curve = decelerateEasing; expect Easing.legacyDecelerate
+  // Changes made in https://github.com/flutter/flutter/pull/134417
+  const Curve curve = standardEasing;
+  const Curve curve = accelerateEasing;
+  const Curve curve = decelerateEasing;
 
   final PlatformMenuBar platformMenuBar = PlatformMenuBar(menus: <PlatformMenuItem>[], body: const SizedBox());
   final Widget bodyValue = platformMenuBar.body;

packages/flutter/test_fixes/material/material.dart.expect

@@ -314,11 +314,10 @@ void main() {
   );
   final Clip clip = details.decorationClipBehavior;
 
-  // Changes made in https://github.com/flutter/flutter/pull/129942
-  // TODO(guidezpl): enable fix after https://github.com/dart-lang/sdk/issues/52902
-  // const Curve curve = standardEasing; expect Easing.legacy
-  // const Curve curve = accelerateEasing; expect Easing.legacyAccelerate
-  // const Curve curve = decelerateEasing; expect Easing.legacyDecelerate
+  // Changes made in https://github.com/flutter/flutter/pull/134417
+  const Curve curve = Easing.legacy;
+  const Curve curve = Easing.legacyAccelerate;
+  const Curve curve = Easing.legacyDecelerate;
 
   final PlatformMenuBar platformMenuBar = PlatformMenuBar(menus: <PlatformMenuItem>[], child: const SizedBox());
   final Widget bodyValue = platformMenuBar.child;