[CPU Profiler] Delete the "Profile app start up" button (#9358)

diff --git a/packages/devtools_app/lib/src/screens/profiler/panes/controls/profiler_screen_controls.dart b/packages/devtools_app/lib/src/screens/profiler/panes/controls/profiler_screen_controls.dart
index 9b3bd43..fbc7cb0 100644
--- a/packages/devtools_app/lib/src/screens/profiler/panes/controls/profiler_screen_controls.dart
+++ b/packages/devtools_app/lib/src/screens/profiler/panes/controls/profiler_screen_controls.dart
@@ -7,7 +7,6 @@
 
 import '../../../../shared/analytics/constants.dart' as gac;
 import '../../../../shared/framework/screen.dart';
-import '../../../../shared/globals.dart';
 import '../../../../shared/ui/common_widgets.dart';
 import '../../../../shared/ui/file_import.dart';
 import '../../../../shared/ui/vm_flag_widgets.dart';
@@ -103,25 +102,6 @@
     return Row(
       mainAxisAlignment: MainAxisAlignment.end,
       children: [
-        if (serviceConnection
-            .serviceManager
-            .connectedApp!
-            .isFlutterNativeAppNow)
-          GaDevToolsButton(
-            icon: Icons.timer,
-            label: 'Profile app start up',
-            tooltip:
-                'Load all Dart CPU samples that occurred before \n'
-                'the first Flutter frame was drawn (if available)',
-            tooltipPadding: const EdgeInsets.all(denseSpacing),
-            gaScreen: gac.cpuProfiler,
-            gaSelection: gac.CpuProfilerEvents.profileAppStartUp.name,
-            minScreenWidthForText: _profilingControlsMinScreenWidthForText,
-            onPressed: !profilerBusy
-                ? controller.cpuProfilerController.loadAppStartUpProfile
-                : null,
-          ),
-        const SizedBox(width: denseSpacing),
         RefreshButton(
           label: 'Load all CPU samples',
           tooltip:
diff --git a/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md b/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md
index 6153c0d..23669cd 100644
--- a/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md
+++ b/packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md
@@ -27,7 +27,9 @@
 
 ## CPU profiler updates
 
-TODO: Remove this section if there are not any general updates.
+- Deleted the "Profile app start up" button in favor of the new Dart/Flutter
+  `--profile-startup` CLI flags. -
+  [#9358](https://github.com/flutter/devtools/pull/9358)
 
 ## Memory updates
 
diff --git a/packages/devtools_app/test/screens/cpu_profiler/profiler_screen_test.dart b/packages/devtools_app/test/screens/cpu_profiler/profiler_screen_test.dart
index dd16f10..0d6914b 100644
--- a/packages/devtools_app/test/screens/cpu_profiler/profiler_screen_test.dart
+++ b/packages/devtools_app/test/screens/cpu_profiler/profiler_screen_test.dart
@@ -34,13 +34,6 @@
       expect(find.byType(StartStopRecordingButton), findsOneWidget);
       expect(find.byType(ClearButton), findsOneWidget);
       expect(find.text('Load all CPU samples'), findsOneWidget);
-      if (scene
-          .fakeServiceConnection
-          .serviceManager
-          .connectedApp!
-          .isFlutterNativeAppNow) {
-        expect(find.text('Profile app start up'), findsOneWidget);
-      }
       expect(find.byType(CpuSamplingRateDropdown), findsOneWidget);
       expect(find.byType(OpenSaveButtonGroup), findsOneWidget);
       expect(find.byType(ProfileRecordingInstructions), findsOneWidget);