[CPU Profiler] Deprecate the "Profile app start up" button

Author: derekxu16

packages/devtools_app/lib/src/screens/profiler/panes/controls/profiler_screen_controls.dart

@@ -111,15 +111,15 @@ class _SecondaryControls extends StatelessWidget {
             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)',
+                'This button is deprecated. The new procedure for profiling an'
+                "\napp's startup is to set the `--profile-startup` CLI\nflag "
+                'when starting the app, and then to use the "Load all CPU\n'
+                'samples" button that is next to this one.',
             tooltipPadding: const EdgeInsets.all(denseSpacing),
             gaScreen: gac.cpuProfiler,
             gaSelection: gac.CpuProfilerEvents.profileAppStartUp.name,
             minScreenWidthForText: _profilingControlsMinScreenWidthForText,
-            onPressed: !profilerBusy
-                ? controller.cpuProfilerController.loadAppStartUpProfile
-                : null,
+            onPressed: null,
           ),
         const SizedBox(width: denseSpacing),
         RefreshButton(

packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md

@@ -29,7 +29,9 @@ TODO: Remove this section if there are not any general updates.
 
 ## CPU profiler updates
 
-TODO: Remove this section if there are not any general updates.
+- Deprecated 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
 

packages/devtools_app/test/screens/cpu_profiler/profiler_screen_test.dart

@@ -30,7 +30,7 @@ void main() {
   const windowSize = Size(2000.0, 1000.0);
 
   group('ProfilerScreen', () {
-    void verifyBaseState() {
+    void verifyBaseState(WidgetTester tester) {
       expect(find.byType(StartStopRecordingButton), findsOneWidget);
       expect(find.byType(ClearButton), findsOneWidget);
       expect(find.text('Load all CPU samples'), findsOneWidget);
@@ -39,7 +39,37 @@ void main() {
           .serviceManager
           .connectedApp!
           .isFlutterNativeAppNow) {
-        expect(find.text('Profile app start up'), findsOneWidget);
+        final profileAppStartUpButtonTextFinder = find.text(
+          'Profile app start up',
+        );
+        expect(profileAppStartUpButtonTextFinder, findsOneWidget);
+
+        final profileAppStartUpButtonTooltipFinder = find.byTooltip(
+          'This button is deprecated. The new procedure for profiling an\n'
+          "app's startup is to set the `--profile-startup` CLI\nflag when "
+          'starting the app, and then to use the "Load all CPU\nsamples" '
+          'button that is next to this one.',
+        );
+        expect(profileAppStartUpButtonTooltipFinder, findsOneWidget);
+
+        expect(
+          find.descendant(
+            of: profileAppStartUpButtonTooltipFinder,
+            matching: profileAppStartUpButtonTextFinder,
+          ),
+          findsOneWidget,
+        );
+
+        final profileAppStartUpButtonFinder = find.ancestor(
+          of: profileAppStartUpButtonTooltipFinder,
+          matching: find.byType(GaDevToolsButton),
+        );
+        expect(
+          (tester.element(profileAppStartUpButtonFinder).widget
+                  as GaDevToolsButton)
+              .onPressed,
+          null,
+        );
       }
       expect(find.byType(CpuSamplingRateDropdown), findsOneWidget);
       expect(find.byType(OpenSaveButtonGroup), findsOneWidget);
@@ -74,7 +104,7 @@ void main() {
       windowSize,
       (WidgetTester tester) async {
         await pumpProfilerScreen(tester);
-        verifyBaseState();
+        verifyBaseState(tester);
       },
     );
 
@@ -89,7 +119,7 @@ void main() {
           isWebApp: false,
         );
         await pumpProfilerScreen(tester);
-        verifyBaseState();
+        verifyBaseState(tester);
       },
     );
 
@@ -98,7 +128,7 @@ void main() {
       windowSize,
       (WidgetTester tester) async {
         await pumpProfilerScreen(tester);
-        verifyBaseState();
+        verifyBaseState(tester);
 
         // Start recording.
         await tester.tap(find.byType(StartStopRecordingButton));
@@ -118,7 +148,7 @@ void main() {
         // Clear the profile.
         await tester.tap(find.byType(ClearButton));
         await tester.pump();
-        verifyBaseState();
+        verifyBaseState(tester);
       },
     );
 
@@ -147,7 +177,7 @@ void main() {
         await tester.pump(const Duration(seconds: 1));
       });
       await tester.pumpAndSettle();
-      verifyBaseState();
+      verifyBaseState(tester);
     });
   });
 }