Reverts "Drop deprecated hash_code functions (#54000)" (flutter/engine#54002)

Reverts: flutter/engine#54000
Initiated by: chingjun
Reason for reverting: Broke Google Testing.

See b/352191023 for more details.
Original PR Author: kevmoo

Reviewed By: {jonahwilliams}

This change reverts the following previous change:
Fixes https://github.com/flutter/flutter/issues/151679

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -42703,6 +42703,7 @@ ORIGIN: ../../../flutter/lib/ui/experiments/setup_hooks.dart + ../../../flutter/
 ORIGIN: ../../../flutter/lib/ui/experiments/ui.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/floating_point.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/geometry.dart + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/lib/ui/hash_codes.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/hooks.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/io_manager.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/ui/io_manager.h + ../../../flutter/LICENSE
@@ -42865,6 +42866,7 @@ ORIGIN: ../../../flutter/lib/web_ui/lib/canvas.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/channel_buffers.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/compositing.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/geometry.dart + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/lib/web_ui/lib/hash_codes.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/initialization.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/key.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/lerp.dart + ../../../flutter/LICENSE
@@ -45581,6 +45583,7 @@ FILE: ../../../flutter/lib/ui/experiments/setup_hooks.dart
 FILE: ../../../flutter/lib/ui/experiments/ui.dart
 FILE: ../../../flutter/lib/ui/floating_point.h
 FILE: ../../../flutter/lib/ui/geometry.dart
+FILE: ../../../flutter/lib/ui/hash_codes.dart
 FILE: ../../../flutter/lib/ui/hooks.dart
 FILE: ../../../flutter/lib/ui/io_manager.cc
 FILE: ../../../flutter/lib/ui/io_manager.h
@@ -45744,6 +45747,7 @@ FILE: ../../../flutter/lib/web_ui/lib/canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/channel_buffers.dart
 FILE: ../../../flutter/lib/web_ui/lib/compositing.dart
 FILE: ../../../flutter/lib/web_ui/lib/geometry.dart
+FILE: ../../../flutter/lib/web_ui/lib/hash_codes.dart
 FILE: ../../../flutter/lib/web_ui/lib/initialization.dart
 FILE: ../../../flutter/lib/web_ui/lib/key.dart
 FILE: ../../../flutter/lib/web_ui/lib/lerp.dart

engine/src/flutter/lib/ui/dart_ui.gni

@@ -7,6 +7,7 @@ dart_ui_files = [
   "//flutter/lib/ui/channel_buffers.dart",
   "//flutter/lib/ui/compositing.dart",
   "//flutter/lib/ui/geometry.dart",
+  "//flutter/lib/ui/hash_codes.dart",
   "//flutter/lib/ui/hooks.dart",
   "//flutter/lib/ui/isolate_name_server.dart",
   "//flutter/lib/ui/key.dart",

engine/src/flutter/lib/ui/experiments/ui.dart

@@ -32,6 +32,7 @@ part '../annotations.dart';
 part '../channel_buffers.dart';
 part '../compositing.dart';
 part '../geometry.dart';
+part '../hash_codes.dart';
 part '../hooks.dart';
 part '../isolate_name_server.dart';
 part '../key.dart';

engine/src/flutter/lib/ui/hash_codes.dart

@@ -0,0 +1,151 @@
+// 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.
+part of dart.ui;
+
+// Examples can assume:
+// int foo = 0;
+// int bar = 0;
+// List<int> quux = <int>[];
+// List<int>? thud;
+// int baz = 0;
+
+class _HashEnd { const _HashEnd(); }
+const _HashEnd _hashEnd = _HashEnd();
+
+// ignore: avoid_classes_with_only_static_members
+/// Jenkins hash function, optimized for small integers.
+//
+// Borrowed from the dart sdk: sdk/lib/math/jenkins_smi_hash.dart.
+class _Jenkins {
+  static int combine(int hash, Object? o) {
+    assert(o is! Iterable);
+    hash = 0x1fffffff & (hash + o.hashCode);
+    hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
+    return hash ^ (hash >> 6);
+  }
+
+  static int finish(int hash) {
+    hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
+    hash = hash ^ (hash >> 11);
+    return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
+  }
+}
+
+/// ## Deprecation
+///
+/// This function has been replaced by [Object.hash], so that it can be used
+/// outside of Flutter as well. The new function is a drop-in replacement.
+///
+/// The [hashList] function has also been replaced, [Object.hashAll] is the new
+/// function. The example above therefore is better written as:
+///
+/// ```dart
+/// int get hashCode => Object.hash(foo, bar, Object.hashAll(quux), baz);
+/// ```
+///
+/// If a parameter is nullable, then it needs special handling,
+/// because [Object.hashAll]'s argument is not nullable:
+///
+/// ```dart
+/// int get hashCode => Object.hash(foo, bar, thud == null ? null : Object.hashAll(thud!), baz);
+/// ```
+@Deprecated(
+  'Use Object.hash() instead. '
+  'This feature was deprecated in v3.1.0-0.0.pre.897'
+)
+int hashValues(
+  Object? arg01,            Object? arg02,          [ Object? arg03 = _hashEnd,
+  Object? arg04 = _hashEnd, Object? arg05 = _hashEnd, Object? arg06 = _hashEnd,
+  Object? arg07 = _hashEnd, Object? arg08 = _hashEnd, Object? arg09 = _hashEnd,
+  Object? arg10 = _hashEnd, Object? arg11 = _hashEnd, Object? arg12 = _hashEnd,
+  Object? arg13 = _hashEnd, Object? arg14 = _hashEnd, Object? arg15 = _hashEnd,
+  Object? arg16 = _hashEnd, Object? arg17 = _hashEnd, Object? arg18 = _hashEnd,
+  Object? arg19 = _hashEnd, Object? arg20 = _hashEnd ]) {
+  int result = 0;
+  result = _Jenkins.combine(result, arg01);
+  result = _Jenkins.combine(result, arg02);
+  if (!identical(arg03, _hashEnd)) {
+    result = _Jenkins.combine(result, arg03);
+    if (!identical(arg04, _hashEnd)) {
+      result = _Jenkins.combine(result, arg04);
+      if (!identical(arg05, _hashEnd)) {
+        result = _Jenkins.combine(result, arg05);
+        if (!identical(arg06, _hashEnd)) {
+          result = _Jenkins.combine(result, arg06);
+          if (!identical(arg07, _hashEnd)) {
+            result = _Jenkins.combine(result, arg07);
+            if (!identical(arg08, _hashEnd)) {
+              result = _Jenkins.combine(result, arg08);
+              if (!identical(arg09, _hashEnd)) {
+                result = _Jenkins.combine(result, arg09);
+                if (!identical(arg10, _hashEnd)) {
+                  result = _Jenkins.combine(result, arg10);
+                  if (!identical(arg11, _hashEnd)) {
+                    result = _Jenkins.combine(result, arg11);
+                    if (!identical(arg12, _hashEnd)) {
+                      result = _Jenkins.combine(result, arg12);
+                      if (!identical(arg13, _hashEnd)) {
+                        result = _Jenkins.combine(result, arg13);
+                        if (!identical(arg14, _hashEnd)) {
+                          result = _Jenkins.combine(result, arg14);
+                          if (!identical(arg15, _hashEnd)) {
+                            result = _Jenkins.combine(result, arg15);
+                            if (!identical(arg16, _hashEnd)) {
+                              result = _Jenkins.combine(result, arg16);
+                              if (!identical(arg17, _hashEnd)) {
+                                result = _Jenkins.combine(result, arg17);
+                                if (!identical(arg18, _hashEnd)) {
+                                  result = _Jenkins.combine(result, arg18);
+                                  if (!identical(arg19, _hashEnd)) {
+                                    result = _Jenkins.combine(result, arg19);
+                                    if (!identical(arg20, _hashEnd)) {
+                                      result = _Jenkins.combine(result, arg20);
+                                      // I can see my house from here!
+                                    }
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  return _Jenkins.finish(result);
+}
+
+/// Combine the [Object.hashCode] values of an arbitrary number of objects from
+/// an [Iterable] into one value. This function will return the same value if
+/// given null as if given an empty list.
+///
+/// ## Deprecation
+///
+/// This function has been replaced by [Object.hashAll], so that it can be used
+/// outside of Flutter as well. The new function is a drop-in replacement, except
+/// that the argument must not be null.
+///
+/// There is also a new function, [Object.hashAllUnordered], which is similar
+/// but returns the same hash code regardless of the order of the elements in
+/// the provided iterable.
+@Deprecated(
+  'Use Object.hashAll() or Object.hashAllUnordered() instead. '
+  'This feature was deprecated in v3.1.0-0.0.pre.897'
+)
+int hashList(Iterable<Object?>? arguments) {
+  int result = 0;
+  if (arguments != null) {
+    for (final Object? argument in arguments) {
+      result = _Jenkins.combine(result, argument);
+    }
+  }
+  return _Jenkins.finish(result);
+}

engine/src/flutter/lib/ui/ui.dart

@@ -32,6 +32,7 @@ part 'annotations.dart';
 part 'channel_buffers.dart';
 part 'compositing.dart';
 part 'geometry.dart';
+part 'hash_codes.dart';
 part 'hooks.dart';
 part 'isolate_name_server.dart';
 part 'key.dart';

engine/src/flutter/lib/web_ui/lib/hash_codes.dart

@@ -0,0 +1,135 @@
+// 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.
+
+part of ui;
+
+class _HashEnd { const _HashEnd(); }
+const _HashEnd _hashEnd = _HashEnd();
+
+// ignore: avoid_classes_with_only_static_members
+/// Jenkins hash function, optimized for small integers.
+//
+// Borrowed from the dart sdk: sdk/lib/math/jenkins_smi_hash.dart.
+class _Jenkins {
+  static int combine(int hash, Object? o) {
+    assert(o is! Iterable);
+    hash = 0x1fffffff & (hash + o.hashCode);
+    hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
+    return hash ^ (hash >> 6);
+  }
+
+  static int finish(int hash) {
+    hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
+    hash = hash ^ (hash >> 11);
+    return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
+  }
+}
+
+/// ## Deprecation
+///
+/// This function has been replaced by [Object.hash], so that it can be used
+/// outside of Flutter as well. The new function is a drop-in replacement.
+///
+/// The [hashList] function has also been replaced, [Object.hashAll] is the new
+/// function. The example above therefore is better written as:
+///
+/// ```dart
+/// int get hashCode => Object.hash(foo, bar, Object.hashAll(quux), baz);
+/// ```
+///
+/// If a parameter is nullable, then it needs special handling,
+/// because [Object.hashAll]'s argument is not nullable:
+///
+/// ```dart
+/// int get hashCode => Object.hash(foo, bar, thud == null ? null : Object.hashAll(thud!), baz);
+/// ```
+@Deprecated(
+  'Use Object.hash() instead. '
+  'This feature was deprecated in v3.1.0-0.0.pre.897'
+)
+int hashValues(
+  Object? arg01,            Object? arg02,          [ Object? arg03 = _hashEnd,
+  Object? arg04 = _hashEnd, Object? arg05 = _hashEnd, Object? arg06 = _hashEnd,
+  Object? arg07 = _hashEnd, Object? arg08 = _hashEnd, Object? arg09 = _hashEnd,
+  Object? arg10 = _hashEnd, Object? arg11 = _hashEnd, Object? arg12 = _hashEnd,
+  Object? arg13 = _hashEnd, Object? arg14 = _hashEnd, Object? arg15 = _hashEnd,
+  Object? arg16 = _hashEnd, Object? arg17 = _hashEnd, Object? arg18 = _hashEnd,
+  Object? arg19 = _hashEnd, Object? arg20 = _hashEnd ]) {
+  int result = 0;
+  result = _Jenkins.combine(result, arg01);
+  result = _Jenkins.combine(result, arg02);
+  if (!identical(arg03, _hashEnd)) {
+    result = _Jenkins.combine(result, arg03);
+    if (!identical(arg04, _hashEnd)) {
+      result = _Jenkins.combine(result, arg04);
+      if (!identical(arg05, _hashEnd)) {
+        result = _Jenkins.combine(result, arg05);
+        if (!identical(arg06, _hashEnd)) {
+          result = _Jenkins.combine(result, arg06);
+          if (!identical(arg07, _hashEnd)) {
+            result = _Jenkins.combine(result, arg07);
+            if (!identical(arg08, _hashEnd)) {
+              result = _Jenkins.combine(result, arg08);
+              if (!identical(arg09, _hashEnd)) {
+                result = _Jenkins.combine(result, arg09);
+                if (!identical(arg10, _hashEnd)) {
+                  result = _Jenkins.combine(result, arg10);
+                  if (!identical(arg11, _hashEnd)) {
+                    result = _Jenkins.combine(result, arg11);
+                    if (!identical(arg12, _hashEnd)) {
+                      result = _Jenkins.combine(result, arg12);
+                      if (!identical(arg13, _hashEnd)) {
+                        result = _Jenkins.combine(result, arg13);
+                        if (!identical(arg14, _hashEnd)) {
+                          result = _Jenkins.combine(result, arg14);
+                          if (!identical(arg15, _hashEnd)) {
+                            result = _Jenkins.combine(result, arg15);
+                            if (!identical(arg16, _hashEnd)) {
+                              result = _Jenkins.combine(result, arg16);
+                              if (!identical(arg17, _hashEnd)) {
+                                result = _Jenkins.combine(result, arg17);
+                                if (!identical(arg18, _hashEnd)) {
+                                  result = _Jenkins.combine(result, arg18);
+                                  if (!identical(arg19, _hashEnd)) {
+                                    result = _Jenkins.combine(result, arg19);
+                                    if (!identical(arg20, _hashEnd)) {
+                                      result = _Jenkins.combine(result, arg20);
+                                      // I can see my house from here!
+                                    }
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  return _Jenkins.finish(result);
+}
+
+/// Combine the [Object.hashCode] values of an arbitrary number of objects from
+/// an [Iterable] into one value. This function will return the same value if
+/// given null as if given an empty list.
+@Deprecated(
+  'Use Object.hashAll() or Object.hashAllUnordered() instead. '
+  'This feature was deprecated in v3.1.0-0.0.pre.897'
+)
+int hashList(Iterable<Object?>? arguments) {
+  int result = 0;
+  if (arguments != null) {
+    for (final Object? argument in arguments) {
+      result = _Jenkins.combine(result, argument);
+    }
+  }
+  return _Jenkins.finish(result);
+}

engine/src/flutter/lib/web_ui/lib/ui.dart

@@ -21,6 +21,7 @@ part 'canvas.dart';
 part 'channel_buffers.dart';
 part 'compositing.dart';
 part 'geometry.dart';
+part 'hash_codes.dart';
 part 'initialization.dart';
 part 'key.dart';
 part 'lerp.dart';

engine/src/flutter/lib/web_ui/test/engine/hash_codes_test.dart

@@ -0,0 +1,119 @@
+// 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.
+
+import 'package:test/bootstrap/browser.dart';
+import 'package:test/test.dart';
+import 'package:ui/ui.dart';
+
+// The biggest integer value that can be represented in JavaScript is 1 << 53.
+// However, the 1 << 53 expression cannot be used in JavaScript because that
+// would apply the bitwise shift to a "number" (i.e. float64), which is
+// meaningless. Instead, a decimal literal is used here.
+const int _kBiggestExactJavaScriptInt = 9007199254740992;
+
+void main() {
+  internalBootstrapBrowserTest(() => testMain);
+}
+
+void testMain() {
+  test('hashValues and hashList can hash lots of huge values effectively', () {
+    final int hashValueFromArgs = hashValues(
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+    );
+
+    // Hash the same values via a list
+    final int hashValueFromList = hashList(<int>[
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+    ]);
+
+    // Hash a slightly smaller number to verify that the hash code is different.
+    final int slightlyDifferentHashValueFromArgs = hashValues(
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt,
+      _kBiggestExactJavaScriptInt - 1,
+    );
+
+    final int slightlyDifferentHashValueFromList = hashList(<int>[
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt,
+        _kBiggestExactJavaScriptInt - 1,
+    ]);
+
+    expect(hashValueFromArgs, equals(hashValueFromList));
+    expect(slightlyDifferentHashValueFromArgs, equals(slightlyDifferentHashValueFromList));
+    expect(hashValueFromArgs, isNot(equals(slightlyDifferentHashValueFromArgs)));
+  });
+}