fix: ensure context-menu emitted for draggable regions (#44799)

* fix: ensure context-menu emitted for draggable regions

Co-authored-by: Shelley Vohr <shelley.vohr@gmail.com>

* chore: address suggestions from review

Co-authored-by: Shelley Vohr <shelley.vohr@gmail.com>

---------

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Shelley Vohr <shelley.vohr@gmail.com>

shell/browser/ui/cocoa/electron_ns_window.mm

@@ -7,6 +7,8 @@
 #include "base/strings/sys_string_conversions.h"
 #include "electron/mas.h"
 #include "shell/browser/native_window_mac.h"
+#include "shell/browser/ui/cocoa/delayed_native_view_host.h"
+#include "shell/browser/ui/cocoa/electron_inspectable_web_contents_view.h"
 #include "shell/browser/ui/cocoa/electron_preview_item.h"
 #include "shell/browser/ui/cocoa/electron_touch_bar.h"
 #include "shell/browser/ui/cocoa/root_view_mac.h"
@@ -189,6 +191,42 @@ void SwizzleSwipeWithEvent(NSView* view, SEL swiz_selector) {
 
 // NSWindow overrides.
 
+- (void)sendEvent:(NSEvent*)event {
+  // Draggable regions only respond to left-click dragging, but the system will
+  // still suppress right-clicks in a draggable region. Forwarding right-clicks
+  // and ctrl+left-clicks allows the underlying views to respond to right-click
+  // to potentially bring up a frame context menu. WebContentsView is now a
+  // sibling view of the NSWindow contentView, so we need to intercept the event
+  // here as NativeWidgetMacNSWindow won't forward it to the WebContentsView
+  // anymore.
+  if (event.type == NSEventTypeRightMouseDown ||
+      (event.type == NSEventTypeLeftMouseDown &&
+       ([event modifierFlags] & NSEventModifierFlagControl))) {
+    // The WebContentsView is added a sibling of BaseWindow's contentView at
+    // index 0 before it in the paint order - see
+    // https://github.com/electron/electron/pull/41256.
+    const auto& children = shell_->GetContentsView()->children();
+    if (children.empty())
+      return;
+
+    auto* wcv = children.front().get();
+    if (!wcv)
+      return;
+
+    auto ns_view = static_cast<electron::DelayedNativeViewHost*>(wcv)
+                       ->GetNativeView()
+                       .GetNativeNSView();
+    if (!ns_view)
+      return;
+
+    [static_cast<ElectronInspectableWebContentsView*>(ns_view)
+        redispatchContextMenuEvent:base::apple::OwnedNSEvent(event)];
+    return;
+  }
+
+  [super sendEvent:event];
+}
+
 - (void)rotateWithEvent:(NSEvent*)event {
   shell_->NotifyWindowRotateGesture(event.rotation);
 }