[Mac] Let embedded NSTextViews handle certain accelerators if focused

If an NSTextView has focus, always allow it to handle Cmd-[acxvz]
accelerators.

This depends upon bockbuild 2ef2dbdc7644a941d3665357bb760047dc05ff1d

Fixes https://bugzilla.xamarin.com/show_bug.cgi?id=20732

main/src/core/Mono.Texteditor/Mono.TextEditor/Gui/GtkWorkarounds.cs

@@ -75,6 +75,9 @@ public static class GtkWorkarounds
 		[DllImport (PangoUtil.LIBQUARTZ)]
 		static extern IntPtr gdk_quartz_window_get_nswindow (IntPtr window);
 
+		[DllImport (PangoUtil.LIBQUARTZ)]
+		static extern bool gdk_window_has_embedded_nsview_focus (IntPtr window);
+
 		struct CGRect32
 		{
 			public float X, Y, Width, Height;
@@ -815,6 +818,19 @@ public static void UpdateNativeShadow (Gtk.Window window)
 			objc_msgSend_IntPtr (ptr, sel_invalidateShadow);
 		}
 
+		public static bool HasNSTextFieldFocus (Gdk.Window window)
+		{
+			if (Platform.IsMac) {
+				try {
+					return gdk_window_has_embedded_nsview_focus (window.Handle);
+				} catch (Exception e) {
+					return false;
+				}
+			} else {
+				return false;
+			}
+		}
+
 		[DllImport (PangoUtil.LIBGTKGLUE, CallingConvention = CallingConvention.Cdecl)]
 		static extern void gtksharp_container_leak_fixed_marker ();
 

main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Commands/CommandManager.cs

@@ -303,18 +303,37 @@ bool CanUseBinding (KeyboardShortcut[] chords, KeyboardShortcut[] accels, out Ke
 		}
 
 		public event EventHandler<KeyBindingFailedEventArgs> KeyBindingFailed;
-
+
+		bool IsShortcutHandledByEmbeddedNSView (Gdk.Window window, KeyboardShortcut[] accels)
+		{
+			if (Mono.TextEditor.GtkWorkarounds.HasNSTextFieldFocus (window)) {
+				foreach (KeyboardShortcut ks in accels) {
+					if (ks.Modifier == Gdk.ModifierType.MetaMask && (
+					        ks.Key == Gdk.Key.a || ks.Key == Gdk.Key.c ||
+					        ks.Key == Gdk.Key.x || ks.Key == Gdk.Key.v ||
+					        ks.Key == Gdk.Key.z)) {
+						return true;
+					}
+				}
+			}
+
+			return false;
+		}
+
 		[GLib.ConnectBefore]
 		void OnKeyPressed (object o, Gtk.KeyPressEventArgs e)
 		{
 			if (!IsEnabled)
 				return;
-			
+
 			RegisterUserInteraction ();
 
 			bool complete;
 			KeyboardShortcut[] accels = KeyBindingManager.AccelsFromKey (e.Event, out complete);
-
+
+			if (IsShortcutHandledByEmbeddedNSView (e.Event.Window, accels))
+				return;
+
 			if (!complete) {
 				// incomplete accel
 				e.RetVal = true;