Manually emit focused event on mouse click

CHANGELOG.md

@@ -19,6 +19,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - On X11, fix for repeated event loop iteration when `ControlFlow` was `Wait`
 - On X11, fix scale factor calculation when the only monitor is reconnected
 - On Wayland, report unaccelerated mouse deltas in `DeviceEvent::MouseMotion`.
+- On web, a focused event is manually generated when a click occurs to emulate behaviour of other backends.
 - **Breaking:** Bump `ndk` version to 0.6, ndk-sys to `v0.3`, `ndk-glue` to `0.6`.
 - Remove no longer needed `WINIT_LINK_COLORSYNC` environment variable.
 - **Breaking:** Rename the `Exit` variant of `ControlFlow` to `ExitWithCode`, which holds a value to control the exit code after running. Add an `Exit` constant which aliases to `ExitWithCode(0)` instead to avoid major breakage. This shouldn't affect most existing programs.

src/platform_impl/web/event_loop/window_target.rs

@@ -160,13 +160,17 @@ impl<T> EventLoopWindowTarget<T> {
             // user code has the correct cursor position.
             runner.send_events(
                 std::iter::once(Event::WindowEvent {
+                    window_id: RootWindowId(id),
+                    event: WindowEvent::Focused(true),
+                })
+                .chain(std::iter::once(Event::WindowEvent {
                     window_id: RootWindowId(id),
                     event: WindowEvent::CursorMoved {
                         device_id: RootDeviceId(DeviceId(pointer_id)),
                         position,
                         modifiers,
                     },
-                })
+                }))
                 .chain(std::iter::once(Event::WindowEvent {
                     window_id: RootWindowId(id),
                     event: WindowEvent::MouseInput {