Allow Widget to pass accelerator handling to its parent.

ui/views/widget/native_widget_mac.mm

Index: ui/views/widget/native_widget_mac.mm
diff --git a/ui/views/widget/native_widget_mac.mm b/ui/views/widget/native_widget_mac.mm
index 1c6b46af73aa14cc9f57f8c992814b6d89d6e700..ee2b890960833a12e91e148c2d2368df751e8639 100644
--- a/ui/views/widget/native_widget_mac.mm
+++ b/ui/views/widget/native_widget_mac.mm
@@ -24,6 +24,7 @@
 #import "ui/views/cocoa/bridged_native_widget.h"
 #include "ui/views/cocoa/cocoa_mouse_capture.h"
 #import "ui/views/cocoa/drag_drop_client_mac.h"
+#import "ui/views/cocoa/native_widget_mac_accelerator_handler.h"
 #import "ui/views/cocoa/native_widget_mac_nswindow.h"
 #import "ui/views/cocoa/views_nswindow_delegate.h"
 #include "ui/views/widget/drop_helper.h"
@@ -121,8 +122,20 @@ int NativeWidgetMac::SheetPositionY() {
 void NativeWidgetMac::InitNativeWidget(const Widget::InitParams& params) {
   ownership_ = params.ownership;
   name_ = params.name;
-  base::scoped_nsobject<NSWindow> window([CreateNSWindow(params) retain]);
+  NativeWidgetMacNSWindow* ns_window = CreateNSWindow(params);
+  base::scoped_nsobject<NSWindow> window([ns_window retain]);

[tapted, 2017/01/02 23:11:49]

if you are just after the concrete type, you can make this a
base::scoped_nsobject<NativeWidgetMacNSWindow>

   [window setReleasedWhenClosed:NO];  // Owned by scoped_nsobject.
+
+  if (params.parent && params.pass_accelerator_to_parent) {

[tapted, 2017/01/02 23:11:49]

I don't think we need params.pass_accelerator_to_parent . Here I'd try something
like

if (![window commandHandler] &&
    [[params.parent window]
conformsToProtocol:@protcol(CommandDispatchingWindow)) {
  id<CommandDispatchingWindow> command_window = [params.parent window];
  [window setCommandHandler:[command_window commandHandler]];
}

+    if (auto* bridge =
+            NativeWidgetMac::GetBridgeForNativeWindow([params.parent window])) {
+      DCHECK(bridge->ns_window());
+      [ns_window setCommandHandler:[[[NativeWidgetMacAcceleratorHandler alloc]
+                                       initWithParentWindow:bridge->ns_window()]
+                                       autorelease]];
+    }
+  }
+
   bridge_->Init(window, params);
 
   // Only set always-on-top here if it is true since setting it may affect how