update from flutter/engine master

.clang-tidy

@@ -0,0 +1,50 @@
+# A YAML format of https://clang.llvm.org/extra/clang-tidy/.
+
+# Prefix check with "-" to ignore.
+Checks: >-
+  bugprone-argument-comment,
+  bugprone-use-after-move,
+  bugprone-unchecked-optional-access,
+  clang-analyzer-*,
+  clang-diagnostic-*,
+  darwin-*,
+  google-*,
+  modernize-use-default-member-init,
+  objc-*,
+  -objc-nsinvocation-argument-lifetime,
+  readability-identifier-naming,
+  -google-build-using-namespace,
+  -google-default-arguments,
+  -google-objc-global-variable-declaration,
+  -google-objc-avoid-throwing-exception,
+  -google-readability-casting,
+  -clang-analyzer-nullability.NullPassedToNonnull,
+  -clang-analyzer-nullability.NullablePassedToNonnull,
+  -clang-analyzer-nullability.NullReturnedFromNonnull,
+  -clang-analyzer-nullability.NullableReturnedFromNonnull,
+  performance-move-const-arg,
+  performance-unnecessary-value-param
+
+CheckOptions:
+  - key: modernize-use-default-member-init.UseAssignment
+    value: true
+  - key: readability-identifier-naming.EnumConstantCase
+    value: "CamelCase"
+  - key: readability-identifier-naming.EnumConstantPrefix
+    value: "k"
+  - key: readability-identifier-naming.GlobalConstantCase
+    value: "CamelCase"
+  - key: readability-identifier-naming.GlobalConstantPrefix
+    value: "k"
+  - key: readability-identifier-naming.PrivateMemberCase
+    value: "lower_case"
+  - key: readability-identifier-naming.PrivateMemberSuffix
+    value: "_"
+
+# Lint headers within paths that contain "/flutter/" but not:
+# - gen         (generated code, the fact it compiles is good enough™)
+# - third_party (we didn't author most of the code, and can't fix the lints)
+#
+# Note this is because of our buildroot setup, so the full path of a lint is:
+# "../../flutter/impeller/core/runtime_types.h:1:1" as reported.
+HeaderFilterRegex: "(!third_party/)(!gen/).*/flutter/.*"

.github/PULL_REQUEST_TEMPLATE.md

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+*Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.*
+
+*List which issues are fixed by this PR. You must list at least one issue.*
+
+*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*
+
+## Pre-launch Checklist
+
+- [ ] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
+- [ ] I read the [Tree Hygiene] wiki page, which explains my responsibilities.
+- [ ] I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides].
+- [ ] I listed at least one issue that this PR fixes in the description above.
+- [ ] I added new tests to check the change I am making or feature I am adding, or the PR is [test-exempt]. See [testing the engine] for instructions on writing and running engine tests.
+- [ ] I updated/added relevant documentation (doc comments with `///`).
+- [ ] I signed the [CLA].
+- [ ] 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
+[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
+[testing the engine]: https://github.com/flutter/flutter/wiki/Testing-the-engine
+[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

.github/dependabot.yml

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+# See Dependabot documentation for all configuration options:
+# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      time: "22:00" # 10 PM MTV
+      timezone: "America/Los_Angeles"
+    labels:
+      - "autosubmit"
+    ignore:
+      # ignore patch versions, just rely on minor in order to update fewer times
+      - dependency-name: "github/codeql-action"
+        update-types: ["version-update:semver-minor"]
+  - package-ecosystem: "pub"
+    directory: "/lib/web_ui"
+    schedule:
+      interval: "daily"
+    labels:
+      - "autosubmit"

.github/labeler.yml

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+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# See https://github.com/actions/labeler/blob/main/README.md for docs.
+'affects: desktop':
+  - shell/platform/darwin/common/**/*
+  - shell/platform/darwin/macos/**/*
+  - shell/platform/linux/**/*
+  - shell/platform/windows/**/*
+
+embedder:
+  - shell/platform/embedder
+
+'e: impeller':
+  - impeller/**/*
+
+platform-android:
+  - shell/platform/android/**/*
+
+platform-ios:
+  - shell/platform/darwin/common/**/*
+  - shell/platform/darwin/ios/**/*
+
+platform-fuchsia:
+  - shell/platform/fuchsia/**/*
+
+platform-linux:
+  - shell/platform/linux/**/*
+
+platform-macos:
+  - shell/platform/darwin/common/**/*
+  - shell/platform/darwin/macos/**/*
+
+platform-web:
+  - lib/web_ui/**/*
+  - '**/web_sdk/**/*'
+
+platform-windows:
+  - shell/platform/windows/**/*