Export more code in ui_primitives to support Flutter tests. (#832)

Author: polina-c

packages/ui_primitives/TEMP_README.md

@@ -18,5 +18,6 @@ with the following changes:
 2. Remove commented code
 3. Review documentation
 4. Add test coverage
-5. Get green light from Flutter Framework team
-6. Try to remove cycle dependencies
+5. Remove occurrences of word 'flutter'.
+6. Get green light from Flutter Framework team
+7. Try to remove cycle dependencies

packages/ui_primitives/lib/ui_primitives.dart

@@ -4,22 +4,58 @@
 
 export 'src/foundation/assertions.dart'
     show
+        DiagnosticsStackTrace,
         ErrorDescription,
+        ErrorHint,
+        ErrorSpacer,
+        ErrorSummary,
         PartialStackFrame,
         RepetitiveStackFrameFilter,
         StackFilter,
         StackFrame,
         UiError,
-        UiErrorDetails;
+        UiErrorDetails,
+        debugPrintStack;
+
 export 'src/foundation/diagnostics.dart'
     show
         DiagnosticLevel,
         DiagnosticPropertiesBuilder,
         Diagnosticable,
+        DiagnosticableNode,
+        DiagnosticableTree,
+        DiagnosticableTreeMixin,
+        DiagnosticableTreeNode,
+        DiagnosticsBlock,
         DiagnosticsNode,
+        DiagnosticsProperty,
         DiagnosticsSerializationDelegate,
         DiagnosticsTreeStyle,
-        TextTreeConfiguration;
+        DoubleProperty,
+        EnumProperty,
+        FlagProperty,
+        FlagsSummary,
+        IntProperty,
+        IterableProperty,
+        MessageProperty,
+        ObjectFlagProperty,
+        PercentProperty,
+        StringProperty,
+        TextTreeConfiguration,
+        TextTreeRenderer,
+        describeEnum,
+        describeIdentity,
+        kNoDefaultValue,
+        shortHash,
+        singleLineTextConfiguration,
+        sparseTextConfiguration;
 export 'src/foundation/listenable.dart' show Listenable, ValueListenable;
+export 'src/foundation/print.dart'
+    show
+        DebugPrintCallback,
+        debugPrint,
+        debugPrintSynchronously,
+        debugPrintThrottled,
+        debugWordWrap;
 export 'src/foundation/value_notifier.dart' show ValueNotifier;
 export 'src/primitives/basics.dart' show VoidCallback;

packages/ui_primitives/pubspec.yaml

@@ -5,7 +5,7 @@
 name: ui_primitives
 description: Highly experimental package.
 repository: https://github.com/flutter/genui/tree/main/packages/ui_primitives
-version: 0.0.1-dev-002
+version: 0.0.1-dev-003
 
 resolution: workspace