Add analytics for hot reload events (#5300)

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

@@ -87,11 +87,13 @@ class RunCommand extends RunCommandBase {
   String get usagePath {
     Device device = deviceForCommand;
 
+    String command = argResults['hot'] ? 'hotrun' : name;
+
     if (device == null)
-      return name;
+      return command;
 
     // Return 'run/ios'.
-    return '$name/${getNameForTargetPlatform(device.platform)}';
+    return '$command/${getNameForTargetPlatform(device.platform)}';
   }
 
   @override

packages/flutter_tools/lib/src/hot.dart

@@ -342,6 +342,7 @@ class HotRunner extends ResidentRunner {
       await _launchFromDevFS(_package, _mainPath);
       restartStatus.stop(showElapsedTime: true);
     }
+    flutterUsage.sendEvent('hot', 'restart');
   }
 
   /// Returns [true] if the reload was successful.
@@ -373,7 +374,10 @@ class HotRunner extends ResidentRunner {
       reloadStatus.stop(showElapsedTime: true);
       if (!_printReloadReport(reloadReport)) {
         // Reload failed.
+        flutterUsage.sendEvent('hot', 'reload-reject');
         return false;
+      } else {
+        flutterUsage.sendEvent('hot', 'reload');
       }
     } catch (errorMessage) {
       reloadStatus.stop(showElapsedTime: true);