Reorganize constants to be closer to place where they are used.

packages/devtools_app/lib/src/screens/memory/panes/chart/chart_control_pane.dart

@@ -12,7 +12,6 @@ import '../../../../shared/theme.dart';
 import '../../../../shared/utils.dart';
 import '../../memory_controller.dart';
 import '../../primitives/ui.dart';
-import '../../shared/constants.dart';
 import 'chart_pane_controller.dart';
 import 'interval_dropdown.dart';
 
@@ -97,7 +96,6 @@ class _ChartControlPaneState extends State<ChartControlPane>
         ValueListenableBuilder<bool>(
           valueListenable: controller.legendVisibleNotifier,
           builder: (_, legendVisible, __) => IconLabelButton(
-            key: legendKey,
             onPressed: () {
               controller.toggleLegendVisibility();
               if (legendVisible) {

packages/devtools_app/lib/src/screens/memory/panes/chart/legend.dart

@@ -6,14 +6,22 @@ import 'package:flutter/material.dart';
 
 import '../../../../shared/common_widgets.dart';
 import '../../../../shared/theme.dart';
+import '../../../../shared/utils.dart';
 import '../../primitives/painting.dart';
-import '../../shared/constants.dart';
 import 'chart_pane_controller.dart';
 import 'memory_android_chart.dart';
 import 'memory_charts.dart';
 import 'memory_events_pane.dart';
 import 'memory_vm_chart.dart';
 
+late final _legendWidth = scaleByFontFactor(200.0);
+late final _legendTextWidth = scaleByFontFactor(55.0);
+late final _legendHeight1Chart = scaleByFontFactor(200.0);
+late final _legendHeight2Charts = scaleByFontFactor(323.0);
+
+/// Padding for each title in the legend.
+const _legendTitlePadding = EdgeInsets.fromLTRB(5, 0, 0, 4);
+
 class MemoryChartLegend extends StatelessWidget {
   const MemoryChartLegend({
     super.key,
@@ -35,7 +43,7 @@ class MemoryChartLegend extends StatelessWidget {
     final events = eventLegendContent(colorScheme.isLight);
     legendRows.add(
       Container(
-        padding: legendTitlePadding,
+        padding: _legendTitlePadding,
         child: Text('Events Legend', style: legendHeading),
       ),
     );
@@ -56,7 +64,7 @@ class MemoryChartLegend extends StatelessWidget {
     final vms = vmLegendContent(chartController.vm);
     legendRows.add(
       Container(
-        padding: legendTitlePadding,
+        padding: _legendTitlePadding,
         child: Text('Memory Legend', style: legendHeading),
       ),
     );
@@ -74,7 +82,7 @@ class MemoryChartLegend extends StatelessWidget {
       final androids = androidLegendContent(chartController.android);
       legendRows.add(
         Container(
-          padding: legendTitlePadding,
+          padding: _legendTitlePadding,
           child: Text('Android Legend', style: legendHeading),
         ),
       );
@@ -90,10 +98,10 @@ class MemoryChartLegend extends StatelessWidget {
     }
 
     return Container(
-      width: legendWidth,
+      width: _legendWidth,
       // The height is specified here,
       // because [legendRows] are designed to take all available space.
-      height: isAndroidVisible ? legendHeight2Charts : legendHeight1Chart,
+      height: isAndroidVisible ? _legendHeight2Charts : _legendHeight1Chart,
       padding: const EdgeInsets.fromLTRB(0, densePadding, densePadding, 0),
       decoration: BoxDecoration(
         color: colorScheme.defaultBackgroundColor,
@@ -135,7 +143,7 @@ class LegendRow extends StatelessWidget {
         Expanded(
           child: Container(
             padding: EdgeInsets.fromLTRB(leftEdge, 0, 0, 2),
-            width: legendTextWidth + leftEdge,
+            width: _legendTextWidth + leftEdge,
             child: Text(name, style: legendEntry),
           ),
         ),

packages/devtools_app/lib/src/screens/memory/panes/control/primitives.dart

@@ -0,0 +1,9 @@
+// Copyright 2019 The Chromium 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:flutter/foundation.dart';
+
+const memorySourceMenuItemPrefix = 'Source: ';
+const sourcesDropdownKey = Key('Sources Dropdown');
+const sourcesKey = Key('Sources');

packages/devtools_app/lib/src/screens/memory/panes/control/secondary_controls.dart

@@ -15,6 +15,7 @@ import '../../memory_controller.dart';
 import '../../primitives/ui.dart';
 import '../../shared/constants.dart';
 import '../chart/chart_pane_controller.dart';
+import 'primitives.dart';
 import 'settings_dialog.dart';
 import 'source_dropdown.dart';
 

packages/devtools_app/lib/src/screens/memory/panes/control/source_dropdown.dart

@@ -7,7 +7,7 @@ import 'package:flutter/material.dart';
 import '../../../../shared/common_widgets.dart';
 import '../../../../shared/utils.dart';
 import '../../memory_controller.dart';
-import '../../shared/constants.dart';
+import 'primitives.dart';
 
 class SourceDropdownMenuItem<T> extends DropdownMenuItem<T> {
   const SourceDropdownMenuItem({T? value, required Widget child})

packages/devtools_app/lib/src/screens/memory/shared/constants.dart

@@ -2,24 +2,5 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter/material.dart';
-
-import '../../../shared/utils.dart';
-
 /// When to have verbose Dropdown based on media width.
 const verboseDropDownMinimumWidth = 950;
-
-const legendXOffset = 20;
-const legendYOffset = 7.0;
-double get legendWidth => scaleByFontFactor(200.0);
-double get legendTextWidth => scaleByFontFactor(55.0);
-double get legendHeight1Chart => scaleByFontFactor(200.0);
-double get legendHeight2Charts => scaleByFontFactor(323.0);
-
-const memorySourceMenuItemPrefix = 'Source: ';
-final legendKey = GlobalKey(debugLabel: 'Legend Button');
-const sourcesDropdownKey = Key('Sources Dropdown');
-const sourcesKey = Key('Sources');
-
-/// Padding for each title in the legend.
-const legendTitlePadding = EdgeInsets.fromLTRB(5, 0, 0, 4);

packages/devtools_app/test/memory/memory_screen_test.dart

@@ -9,8 +9,8 @@ import 'package:devtools_app/src/screens/memory/memory_screen.dart';
 import 'package:devtools_app/src/screens/memory/panes/chart/chart_control_pane.dart';
 import 'package:devtools_app/src/screens/memory/panes/chart/memory_events_pane.dart';
 import 'package:devtools_app/src/screens/memory/panes/chart/memory_vm_chart.dart';
+import 'package:devtools_app/src/screens/memory/panes/control/primitives.dart';
 import 'package:devtools_app/src/screens/memory/panes/control/source_dropdown.dart';
-import 'package:devtools_app/src/screens/memory/shared/constants.dart';
 import 'package:devtools_app/src/service/service_manager.dart';
 import 'package:devtools_app/src/shared/common_widgets.dart';
 import 'package:devtools_app/src/shared/globals.dart';