Correct contentPadding type in InputDecoration.debugFillProperties (#19318)

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

@@ -2507,7 +2507,7 @@ class InputDecorationTheme extends Diagnosticable {
     properties.add(new DiagnosticsProperty<TextStyle>('errorStyle', errorStyle, defaultValue: defaultTheme.errorStyle));
     properties.add(new DiagnosticsProperty<int>('errorMaxLines', errorMaxLines, defaultValue: defaultTheme.errorMaxLines));
     properties.add(new DiagnosticsProperty<bool>('isDense', isDense, defaultValue: defaultTheme.isDense));
-    properties.add(new DiagnosticsProperty<EdgeInsets>('contentPadding', contentPadding, defaultValue: defaultTheme.contentPadding));
+    properties.add(new DiagnosticsProperty<EdgeInsetsDirectional>('contentPadding', contentPadding, defaultValue: defaultTheme.contentPadding));
     properties.add(new DiagnosticsProperty<bool>('isCollapsed', isCollapsed, defaultValue: defaultTheme.isCollapsed));
     properties.add(new DiagnosticsProperty<TextStyle>('prefixStyle', prefixStyle, defaultValue: defaultTheme.prefixStyle));
     properties.add(new DiagnosticsProperty<TextStyle>('suffixStyle', suffixStyle, defaultValue: defaultTheme.suffixStyle));

packages/flutter/test/material/input_decorator_test.dart

@@ -1639,4 +1639,15 @@ void main() {
     },
     skip: !Platform.isLinux,
   );
+
+  testWidgets('InputDecorationTheme.toString()', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/19305
+
+    expect(
+      const InputDecorationTheme(
+        contentPadding: const EdgeInsetsDirectional.only(start: 5.0),
+      ).toString(),
+      contains('contentPadding: EdgeInsetsDirectional(5.0, 0.0, 0.0, 0.0)'),
+    );
+  });
 }