Adds floatLabelBehavior to InputDecoration (#46115)

packages/flutter/test/material/input_decorator_test.dart

@@ -124,6 +124,7 @@ void main() {
         ),
       ),
     );
+    await tester.pumpAndSettle();
 
     // Overall height for this InputDecorator is 56dps:
     //   12 - top padding
@@ -140,6 +141,59 @@ void main() {
     expect(getBorderBottom(tester), 56.0);
     expect(getBorderWeight(tester), 1.0);
 
+    // The label appears within the input when there is no text content
+    await tester.pumpWidget(
+      buildInputDecorator(
+        isEmpty: true,
+        // isFocused: false (default)
+        decoration: const InputDecoration(
+          labelText: 'label',
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(tester.getTopLeft(find.text('label')).dy, 20.0);
+
+    // The label appears above the input text when there is no content and floatingLabelBehavior is always
+    await tester.pumpWidget(
+      buildInputDecorator(
+        isEmpty: true,
+        // isFocused: false (default)
+        decoration: const InputDecoration(
+          labelText: 'label',
+          floatingLabelBehavior: FloatingLabelBehavior.always
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(tester.getTopLeft(find.text('label')).dy, 12.0);
+
+    // The label appears within the input text when there is content and floatingLabelBehavior is never
+    await tester.pumpWidget(
+      buildInputDecorator(
+        isEmpty: false,
+        // isFocused: false (default)
+        decoration: const InputDecoration(
+          labelText: 'label',
+          floatingLabelBehavior: FloatingLabelBehavior.never
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(tester.getTopLeft(find.text('label')).dy, 20.0);
+
+    // Overall height for this InputDecorator is 56dps:
+    //   12 - top padding
+    //   12 - floating label (ahem font size 16dps * 0.75 = 12)
+    //    4 - floating label / input text gap
+    //   16 - input text (ahem font size 16dps)
+    //   12 - bottom padding
+
+    expect(tester.getTopLeft(find.text('label')).dy, 20.0);
+
     // isFocused: true increases the border's weight from 1.0 to 2.0
     // but does not change the overall height.
     await tester.pumpWidget(
@@ -2476,6 +2530,7 @@ void main() {
         isEmpty: true,
         decoration: const InputDecoration(
           border: OutlineInputBorder(borderSide: BorderSide.none),
+          // ignore: deprecated_member_use_from_same_package
           hasFloatingPlaceholder: false,
           labelText: 'label',
         ),
@@ -2500,6 +2555,7 @@ void main() {
         // isFocused: false (default)
         decoration: const InputDecoration(
           border: OutlineInputBorder(borderSide: BorderSide.none),
+          // ignore: deprecated_member_use_from_same_package
           hasFloatingPlaceholder: false,
           labelText: 'label',
         ),
@@ -2679,7 +2735,7 @@ void main() {
     );
     expect(
       child.toString(),
-      "InputDecorator-[<'key'>](decoration: InputDecoration(), baseStyle: TextStyle(<all styles inherited>), isFocused: false, isEmpty: false)",
+      "InputDecorator-[<'key'>](decoration: InputDecoration(floatingLabelBehavior: FloatingLabelBehavior.auto), baseStyle: TextStyle(<all styles inherited>), isFocused: false, isEmpty: false)",
     );
   });
 
@@ -3509,7 +3565,9 @@ void main() {
       helperMaxLines: 6,
       hintStyle: TextStyle(),
       errorMaxLines: 5,
+      // ignore: deprecated_member_use_from_same_package
       hasFloatingPlaceholder: false,
+      floatingLabelBehavior: FloatingLabelBehavior.never,
       contentPadding: EdgeInsetsDirectional.only(start: 40.0, top: 12.0, bottom: 12.0),
       prefixStyle: TextStyle(),
       suffixStyle: TextStyle(),
@@ -3535,6 +3593,7 @@ void main() {
       'hintStyle: TextStyle(<all styles inherited>)',
       'errorMaxLines: 5',
       'hasFloatingPlaceholder: false',
+      'floatingLabelBehavior: FloatingLabelBehavior.never',
       'contentPadding: EdgeInsetsDirectional(40.0, 12.0, 0.0, 12.0)',
       'prefixStyle: TextStyle(<all styles inherited>)',
       'suffixStyle: TextStyle(<all styles inherited>)',

packages/flutter/test/material/text_field_test.dart

@@ -6565,7 +6565,7 @@ void main() {
 
     expect(description, <String>[
       'enabled: false',
-      'decoration: InputDecoration(labelText: "foo")',
+      'decoration: InputDecoration(labelText: "foo", floatingLabelBehavior: FloatingLabelBehavior.auto)',
       'style: TextStyle(inherit: true, color: Color(0xff00ff00))',
       'autofocus: true',
       'autocorrect: false',