Add Android 14 nonlinear font scaling migration guide (#9425)

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---------

Co-authored-by: Anthony Sansone <atsansone@users.noreply.github.com>

src/release/breaking-changes/android-14-nonlinear-text-scaling-migration.md

@@ -0,0 +1,75 @@
+---
+title: Android 14 nonlinear font scaling enabled after v3.14
+description: >
+  New Android 14 nonlinear font scaling feature is enabled in Flutter after v3.14.
+---
+
+## Summary
+
+Android 14 introduced nonlinear font scaling up to 200%.
+It may change how your app looks when the user changes
+the accessibility text scaling in system preferences.
+
+## Background
+
+The [Android 14 nonlinear font scaling][] feature prevents excessive accessibility 
+font scaling by scaling larger text at a lesser rate when the user increases the 
+text scaling value in system preferences.
+
+## Migration guide
+
+As the [Android 14 feature overview][Android 14 nonlinear font scaling] suggests,
+test your UI with the maximum font size enabled (200%).
+This should verify that your app can apply the font sizes correctly
+and can accommodate larger font sizes without impacting usability.
+
+To adopt nonlinear font scaling in your app and custom widgets,
+consider migrating from `textScaleFactor` to `TextScaler`.
+This migration guide outlines the process:
+[Deprecate `textScaleFactor` in favor of `TextScaler`][], .
+
+**Temporarily Opting Out**
+To opt-out of nonlinear text scaling on Android 14 until you migrate your app,
+add a modified `MediaQuery` at the top of your app's widget tree:
+
+```dart 
+runApp(
+  Builder(builder: (context) {
+    final mediaQueryData = MediaQuery.of(context);
+    final mediaQueryDataWithLinearTextScaling = mediaQueryData
+      .copyWith(textScaler: TextScaler.linear(mediaQueryData.textScaler.textScaleFactor));
+    return MediaQuery(data: mediaQueryDataWithLinearTextScaling, child: realWidgetTree);
+  }),
+);
+```
+This uses the deprecated `textScaleFactor` API.
+It will stop working once that API is removed from the Flutter API.
+
+## Timeline
+
+Landed in version: 3.14.0-11.0.pre<br>
+In stable release: not yet (Not in 3.13)
+
+## References
+
+API documentation:
+
+* [`TextScaler`][]
+
+Relevant issues:
+
+* [New font scaling system (Issue 116231)][]
+
+Relevant PRs:
+
+* [Implementing TextScaler for nonlinear text scaling][]
+
+Seealso: 
+
+* [Deprecate `textScaleFactor` in favor of `TextScaler`][]
+
+[Android 14 nonlinear font scaling]: https://developer.android.com/about/versions/14/features#non-linear-font-scaling
+[Deprecate `textScaleFactor` in favor of `TextScaler`]: {{site.url}}/release/breaking-changes/deprecate-textscalefactor
+[`TextScaler`]: {{site.master-api}}/flutter/painting/TextScaler-class.html
+[New font scaling system (Issue 116231)]: {{site.repo.flutter}}/issues/116231
+[Implementing TextScaler for nonlinear text scaling]: {{site.repo.engine}}/pull/44907

src/release/breaking-changes/index.md

@@ -33,6 +33,7 @@ release, and listed in alphabetical order:
 
 * [Customize tabs alignment using the new `TabBar.tabAlignment` property][]
 * [Deprecate `textScaleFactor` in favor of `TextScaler`][]
+* [Android 14 nonlinear font scaling enabled after v3.14][]
 * [Deprecate TextField.canRequestFocus][]
 * [Deprecate `describeEnum` and update `EnumProperty` to be type strict][]
 * [Deprecated just-in-time navigation pop APIs for Android Predictive Back][]
@@ -44,6 +45,7 @@ release, and listed in alphabetical order:
 
 [Customize tabs alignment using the new `TabBar.tabAlignment` property]: {{site.url}}/release/breaking-changes/tab-alignment
 [Deprecate `textScaleFactor` in favor of `TextScaler`]: {{site.url}}/release/breaking-changes/deprecate-textscalefactor
+[Android 14 nonlinear font scaling enabled after v3.14]: {{site.url}}/release/breaking-changes/android-14-nonlinear-text-scaling-migration
 [Deprecate TextField.canRequestFocus]: {{site.url}}/release/breaking-changes/can-request-focus
 [Deprecate `describeEnum` and update `EnumProperty` to be type strict]: {{site.url}}/release/breaking-changes/describe-enum
 [Deprecated just-in-time navigation pop APIs for Android Predictive Back]: {{site.url}}/release/breaking-changes/android-predictive-back