add option for --verbose-system-logs (#29321)

packages/flutter_tools/lib/src/android/android_device.dart

@@ -439,6 +439,9 @@ class AndroidDevice extends Device {
         cmd.addAll(<String>['--ez', 'start-paused', 'true']);
       if (debuggingOptions.useTestFonts)
         cmd.addAll(<String>['--ez', 'use-test-fonts', 'true']);
+      if (debuggingOptions.verboseSystemLogs) {
+        cmd.addAll(<String>['--ez', '--verbose-logging', 'true']);
+      }
     }
     cmd.add(apk.launchActivity);
     final String result = (await runCheckedAsync(cmd)).stdout;

packages/flutter_tools/lib/src/commands/run.dart

@@ -32,6 +32,10 @@ abstract class RunCommandBase extends FlutterCommand {
         negatable: false,
         help: 'Trace application startup, then exit, saving the trace to a file.',
       )
+      ..addFlag('verbose-system-logs',
+        negatable: false,
+        help: 'Include verbose logging from the flutter engine.'
+      )
       ..addOption('route',
         help: 'Which route to load when running the app.',
       )
@@ -256,6 +260,7 @@ class RunCommand extends RunCommandBase {
         traceSkia: argResults['trace-skia'],
         traceSystrace: argResults['trace-systrace'],
         observatoryPort: observatoryPort,
+        verboseSystemLogs: argResults['verbose-system-logs'],
       );
     }
   }

packages/flutter_tools/lib/src/device.dart

@@ -372,6 +372,7 @@ class DebuggingOptions {
     this.traceSkia = false,
     this.traceSystrace = false,
     this.useTestFonts = false,
+    this.verboseSystemLogs = false,
     this.observatoryPort,
    }) : debuggingEnabled = true;
 
@@ -383,6 +384,7 @@ class DebuggingOptions {
       skiaDeterministicRendering = false,
       traceSkia = false,
       traceSystrace = false,
+      verboseSystemLogs = false,
       observatoryPort = null;
 
   final bool debuggingEnabled;
@@ -394,6 +396,7 @@ class DebuggingOptions {
   final bool traceSkia;
   final bool traceSystrace;
   final bool useTestFonts;
+  final bool verboseSystemLogs;
   final int observatoryPort;
 
   bool get hasObservatoryPort => observatoryPort != null;

packages/flutter_tools/lib/src/ios/devices.dart

@@ -297,6 +297,10 @@ class IOSDevice extends Device {
     if (debuggingOptions.traceSkia)
       launchArguments.add('--trace-skia');
 
+    if (debuggingOptions.verboseSystemLogs) {
+      launchArguments.add('--verbose-logging');
+    }
+
     if (platformArgs['trace-startup'] ?? false)
       launchArguments.add('--trace-startup');