[Mac] Factor out keyboard shortcut handling from ChromeEventProcessingWindow.

ui/views/cocoa/native_widget_mac_nswindow.mm

Index: ui/views/cocoa/native_widget_mac_nswindow.mm
diff --git a/ui/views/cocoa/native_widget_mac_nswindow.mm b/ui/views/cocoa/native_widget_mac_nswindow.mm
index 8799ee15a35550cea141390c6a4f51f9d5de6c6c..dcbcb46dbf1a06770e323b8db5b3409d6b78acb7 100644
--- a/ui/views/cocoa/native_widget_mac_nswindow.mm
+++ b/ui/views/cocoa/native_widget_mac_nswindow.mm
@@ -22,6 +22,20 @@
 
 @implementation NativeWidgetMacNSWindow
 
+- (instancetype)initWithContentRect:(NSRect)contentRect
+                          styleMask:(NSUInteger)windowStyle
+                            backing:(NSBackingStoreType)bufferingType
+                              defer:(BOOL)deferCreation {
+  if ((self = [super initWithContentRect:contentRect
+                               styleMask:windowStyle
+                                 backing:bufferingType
+                                   defer:deferCreation])) {
+    commandDispatcherImpl_.reset(
+        [[CommandDispatcherImpl alloc] initWithOwner:self]);
+  }
+  return self;
+}
+
 - (ViewsNSWindowDelegate*)viewsNSWindowDelegate {
   return base::mac::ObjCCastStrict<ViewsNSWindowDelegate>([self delegate]);
 }
@@ -64,6 +78,10 @@
 // menu while it is active, and while still allowing any native subview to
 // retain firstResponder status.
 - (void)sendEvent:(NSEvent*)event {
+  // Let CommandDispatcherImpl check if this is a redispatched event.
+  if ([commandDispatcherImpl_ preSendEvent:event])
+    return;
+
   NSEventType type = [event type];
   if ((type != NSKeyDown && type != NSKeyUp) || ![self hasViewsMenuActive]) {
     [super sendEvent:event];
@@ -104,6 +122,10 @@
 
 // NSResponder implementation.
 
+- (BOOL)performKeyEquivalent:(NSEvent*)event {
+  return [commandDispatcherImpl_ performKeyEquivalent:event];
+}
+
 - (void)cursorUpdate:(NSEvent*)theEvent {
   // The cursor provided by the delegate should only be applied within the
   // content area. This is because we rely on the contentView to track the
@@ -124,4 +146,18 @@
     [super cursorUpdate:theEvent];
 }
 
+// CommandDispatcher implementation.
+
+- (void)setCommandDispatcherDelegate:(id<CommandDispatcherDelegate>)delegate {
+  [commandDispatcherImpl_ setDelegate:delegate];
+}
+
+- (BOOL)redispatchKeyEvent:(NSEvent*)event {
+  return [commandDispatcherImpl_ redispatchKeyEvent:event];
+}
+
+- (BOOL)defaultPerformKeyEquivalent:(NSEvent*)event {
+  return [super performKeyEquivalent:event];
+}
+
 @end