Merge pull request #4181 from bengotow/scroll-touch-events

Extend NativeWindow to track touch-based scroll events on OS X

atom/browser/api/atom_api_window.cc

@@ -227,6 +227,14 @@ void Window::OnWindowLeaveFullScreen() {
   Emit("leave-full-screen");
 }
 
+void Window::OnWindowScrollTouchBegin() {
+  Emit("scroll-touch-begin");
+}
+
+void Window::OnWindowScrollTouchEnd() {
+  Emit("scroll-touch-end");
+}
+
 void Window::OnWindowEnterHtmlFullScreen() {
   Emit("enter-html-full-screen");
 }

atom/browser/api/atom_api_window.h

@@ -65,6 +65,8 @@ class Window : public mate::TrackableObject<Window>,
   void OnWindowResize() override;
   void OnWindowMove() override;
   void OnWindowMoved() override;
+  void OnWindowScrollTouchBegin() override;
+  void OnWindowScrollTouchEnd() override;
   void OnWindowEnterFullScreen() override;
   void OnWindowLeaveFullScreen() override;
   void OnWindowEnterHtmlFullScreen() override;

atom/browser/native_window.cc

@@ -450,6 +450,16 @@ void NativeWindow::NotifyWindowEnterFullScreen() {
                     OnWindowEnterFullScreen());
 }
 
+void NativeWindow::NotifyWindowScrollTouchBegin() {
+  FOR_EACH_OBSERVER(NativeWindowObserver, observers_,
+                    OnWindowScrollTouchBegin());
+}
+
+void NativeWindow::NotifyWindowScrollTouchEnd() {
+  FOR_EACH_OBSERVER(NativeWindowObserver, observers_,
+                    OnWindowScrollTouchEnd());
+}
+
 void NativeWindow::NotifyWindowLeaveFullScreen() {
   FOR_EACH_OBSERVER(NativeWindowObserver, observers_,
                     OnWindowLeaveFullScreen());

atom/browser/native_window.h

@@ -217,6 +217,8 @@ class NativeWindow : public base::SupportsUserData,
   void NotifyWindowMove();
   void NotifyWindowResize();
   void NotifyWindowMoved();
+  void NotifyWindowScrollTouchBegin();
+  void NotifyWindowScrollTouchEnd();
   void NotifyWindowEnterFullScreen();
   void NotifyWindowLeaveFullScreen();
   void NotifyWindowEnterHtmlFullScreen();

atom/browser/native_window_mac.h

@@ -126,6 +126,7 @@ class NativeWindowMac : public NativeWindow {
 
   base::scoped_nsobject<AtomNSWindow> window_;
   base::scoped_nsobject<AtomNSWindowDelegate> window_delegate_;
+  base::scoped_nsobject<id> event_monitor_;
 
   // The view that will fill the whole frameless window.
   base::scoped_nsobject<FullSizeContentView> content_view_;

atom/browser/native_window_mac.mm

@@ -499,10 +499,32 @@ NativeWindowMac::NativeWindowMac(
   NSView* view = inspectable_web_contents()->GetView()->GetNativeView();
   [view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
 
+  BOOL __block down = NO;
+  event_monitor_.reset([[NSEvent
+    addLocalMonitorForEventsMatchingMask:NSScrollWheelMask
+    handler:^NSEvent * _Nullable(NSEvent * event) {
+      if ([[event window] windowNumber] != [window_ windowNumber])
+        return event;
+
+      if (!web_contents)
+        return event;
+
+      if (!down && (([event phase] == NSEventPhaseMayBegin) || ([event phase] == NSEventPhaseBegan))) {
+        this->NotifyWindowScrollTouchBegin();
+        down = YES;
+      }
+      if (down && (([event phase] == NSEventPhaseEnded) || ([event phase] == NSEventPhaseCancelled))) {
+        this->NotifyWindowScrollTouchEnd();
+        down = NO;
+      }
+      return event;
+  }] retain]);
+
   InstallView();
 }
 
 NativeWindowMac::~NativeWindowMac() {
+  [NSEvent removeMonitor: event_monitor_.get()];
   Observe(nullptr);
 }
 

atom/browser/native_window_observer.h

@@ -50,6 +50,8 @@ class NativeWindowObserver {
   virtual void OnWindowResize() {}
   virtual void OnWindowMove() {}
   virtual void OnWindowMoved() {}
+  virtual void OnWindowScrollTouchBegin() {}
+  virtual void OnWindowScrollTouchEnd() {}
   virtual void OnWindowEnterFullScreen() {}
   virtual void OnWindowLeaveFullScreen() {}
   virtual void OnWindowEnterHtmlFullScreen() {}