Mac: ignore CmdT/N from key repeats

Bug: 635853
Change-Id: I4f4c475e8326b3dc3a5c3014185f027b8656176a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2372739Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Leonard Grey <lgrey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801401}

chrome/browser/ui/cocoa/chrome_command_dispatcher_delegate.mm

@@ -5,6 +5,7 @@
 #import "chrome/browser/ui/cocoa/chrome_command_dispatcher_delegate.h"
 
 #include "base/check.h"
+#include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/global_keyboard_shortcuts_mac.h"
 #include "components/remote_cocoa/app_shim/native_widget_ns_window_bridge.h"
 #include "components/remote_cocoa/common/native_widget_ns_window_host.mojom.h"
@@ -91,6 +92,13 @@
   // By not passing the event to AppKit, we do lose out on the brief
   // highlighting of the NSMenu.
   CommandForKeyEventResult result = CommandForKeyEvent(event);
+  // Ignore new tab/window events if |event| is a key repeat to prevent
+  // users from accidentally opening too many empty tabs or windows.
+  if (event.isARepeat && (result.chrome_command == IDC_NEW_TAB ||
+                          result.chrome_command == IDC_NEW_WINDOW)) {
+    return ui::PerformKeyEquivalentResult::kDrop;
+  }
+
   if (result.found()) {
     auto* bridge =
         remote_cocoa::NativeWidgetNSWindowBridge::GetFromNativeWindow(window);

ui/base/cocoa/command_dispatcher.h

@@ -86,6 +86,11 @@ enum class PerformKeyEquivalentResult {
   // the event to be passed to the MainMenu, which will handle the key
   // equivalent.
   kPassToMainMenu,
+
+  // The CommandDispatcherDelegate determined the event should not be handled.
+  // This can occur when an event has been sent via key repeat that we've
+  // determined should not be triggered via repeat.
+  kDrop,
 };
 
 }  // namespace ui

ui/base/cocoa/command_dispatcher.mm

@@ -130,7 +130,8 @@ NSEvent* KeyEventForWindow(NSWindow* window, NSEvent* event) {
   // First, give the delegate an opportunity to consume this event.
   ui::PerformKeyEquivalentResult result =
       [_delegate prePerformKeyEquivalent:event window:_owner];
-  if (result == ui::PerformKeyEquivalentResult::kHandled)
+  if (result == ui::PerformKeyEquivalentResult::kHandled ||
+      result == ui::PerformKeyEquivalentResult::kDrop)
     return YES;
   if (result == ui::PerformKeyEquivalentResult::kPassToMainMenu)
     return NO;