Enable hover by default for desktop shells (flutter#8991)

Fixes flutter#32835

Author: stuartmorgan-g

shell/platform/darwin/macos/framework/Headers/FLEViewController.h

@@ -48,7 +48,7 @@ FLUTTER_EXPORT
 
 /**
  * The style of mouse tracking to use for the view. Defaults to
- * FlutterMouseTrackingModeNone.
+ * FlutterMouseTrackingModeInKeyWindow.
  */
 @property(nonatomic) FlutterMouseTrackingMode mouseTrackingMode;
 

shell/platform/darwin/macos/framework/Source/FLEViewController.mm

@@ -204,6 +204,7 @@ @implementation FLEViewController {
 static void CommonInit(FLEViewController* controller) {
   controller->_messageHandlers = [[NSMutableDictionary alloc] init];
   controller->_additionalKeyResponders = [[NSMutableOrderedSet alloc] init];
+  controller->_mouseTrackingMode = FlutterMouseTrackingModeInKeyWindow;
 }
 
 - (instancetype)initWithCoder:(NSCoder*)coder {

shell/platform/glfw/flutter_glfw.cc

@@ -85,7 +85,7 @@ struct FlutterDesktopWindow {
   GLFWwindow* window;
 
   // Whether or not to track mouse movements to send kHover events.
-  bool hover_tracking_enabled = false;
+  bool hover_tracking_enabled = true;
 
   // The ratio of pixels per screen coordinate for the window.
   double pixels_per_screen_coordinate = 1.0;

shell/platform/glfw/public/flutter_glfw.h

@@ -98,7 +98,7 @@ FlutterDesktopGetPluginRegistrar(FlutterDesktopWindowControllerRef controller,
 //
 // If hover is enabled, mouse movement will send hover events to the Flutter
 // engine, rather than only tracking the mouse while the button is pressed.
-// Defaults to off.
+// Defaults to on.
 FLUTTER_EXPORT void FlutterDesktopWindowSetHoverEnabled(
     FlutterDesktopWindowRef flutter_window,
     bool enabled);