servo: Merge #8223 - Make executing synthesized pinch zoom more similar to zoom (from mrobinson:pinch-zoom-2); r=pcwalton

Synthesized pinch zoom was removed in #8121 so that this combination of
mouse wheel and key press can be handled by the page. I mistakenly
re-implemented it #8215. In order to preserve synthesized pinch zoom,
which is very useful for testing on desktop computers, have it work
similarly to page zoom except with the ALT key pressed.

Source-Repo: https://github.com/servo/servo
Source-Revision: 526a3c8df3882c83a0512dbb341cf7f1781ac402

servo/ports/glutin/window.rs

@@ -204,17 +204,7 @@ impl Window {
                     MouseScrollDelta::LineDelta(dx, dy) => (dx, dy * LINE_HEIGHT),
                     MouseScrollDelta::PixelDelta(dx, dy) => (dx, dy),
                 };
-
-                if !self.key_modifiers.get().intersects(LEFT_CONTROL | RIGHT_CONTROL) {
                 self.scroll_window(dx, dy);
-                } else {
-                    let factor = if dy > 0. {
-                        1.1
-                    } else {
-                        1.0 / 1.1
-                    };
-                    self.pinch_zoom(factor);
-                }
             },
             Event::Refresh => {
                 self.event_queue.borrow_mut().push(WindowEvent::Refresh);
@@ -234,10 +224,6 @@ impl Window {
         self.key_modifiers.set(modifiers);
     }
 
-    fn pinch_zoom(&self, factor: f32) {
-        self.event_queue.borrow_mut().push(WindowEvent::PinchZoom(factor));
-    }
-
     /// Helper function to send a scroll event.
     fn scroll_window(&self, dx: f32, dy: f32) {
         let mouse_pos = self.mouse_pos.get();
@@ -646,12 +632,19 @@ impl WindowMethods for Window {
     fn handle_key(&self, key: Key, mods: constellation_msg::KeyModifiers) {
 
         match (mods, key) {
-            (_, Key::Equal) if mods & !SHIFT == CMD_OR_CONTROL => {
+            (_, Key::Equal) => {
+                if mods & !SHIFT == CMD_OR_CONTROL {
                     self.event_queue.borrow_mut().push(WindowEvent::Zoom(1.1));
+                } else if mods & !SHIFT == CMD_OR_CONTROL | ALT {
+                    self.event_queue.borrow_mut().push(WindowEvent::PinchZoom(1.1));
+                }
             }
             (CMD_OR_CONTROL, Key::Minus) => {
                 self.event_queue.borrow_mut().push(WindowEvent::Zoom(1.0 / 1.1));
             }
+            (_, Key::Minus) if mods == CMD_OR_CONTROL | ALT => {
+                self.event_queue.borrow_mut().push(WindowEvent::PinchZoom(1.0 / 1.1));
+            }
             (CMD_OR_CONTROL, Key::Num0) |
             (CMD_OR_CONTROL, Key::Kp0) => {
                 self.event_queue.borrow_mut().push(WindowEvent::ResetZoom);