exo: Introduce KeyboardModifiers.

Preparation to move XkbTracker out from components/exo/wayland.
This CL now wraps the dependency to xkbcommon from
wayland_keyboard_delegate.cc

BUG=1123705
TEST=Built locally.

Change-Id: If732a97aff7ccf729f60ea17fc1b193f3244b275
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2416153Reviewed-by: Jun Mukai <mukai@chromium.org>
Commit-Queue: Hidehiko Abe <hidehiko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808727}

components/exo/BUILD.gn

@@ -132,6 +132,7 @@ static_library("exo") {
       "input_method_surface_manager.h",
       "keyboard.cc",
       "keyboard.h",
+      "keyboard_modifiers.h",
       "notification.cc",
       "notification.h",
       "notification_surface.cc",

components/exo/keyboard_modifiers.h

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_EXO_KEYBOARD_MODIFIERS_H_
+#define COMPONENTS_EXO_KEYBOARD_MODIFIERS_H_
+
+#include <stdint.h>
+
+namespace exo {
+
+// Represents keyboard modifiers.
+struct KeyboardModifiers {
+  uint32_t depressed;
+  uint32_t locked;
+  uint32_t latched;
+  uint32_t group;
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_KEYBOARD_MODIFIERS_H_

components/exo/wayland/wayland_keyboard_delegate.cc

@@ -10,6 +10,7 @@
 #include <wayland-server-protocol-core.h>
 
 #include "base/containers/flat_map.h"
+#include "components/exo/keyboard_modifiers.h"
 #include "components/exo/wayland/serial_tracker.h"
 #include "components/exo/xkb_tracker.h"
 #include "ui/events/keycodes/dom/dom_code.h"
@@ -109,13 +110,12 @@ uint32_t WaylandKeyboardDelegate::DomCodeToKey(ui::DomCode code) const {
 }
 
 void WaylandKeyboardDelegate::SendKeyboardModifiers() {
+  const KeyboardModifiers modifiers = xkb_tracker_->GetModifiers();
   wl_keyboard_send_modifiers(
       keyboard_resource_,
       serial_tracker_->GetNextSerial(SerialTracker::EventType::OTHER_EVENT),
-      xkb_tracker_->GetSerializeMods(XKB_STATE_MODS_DEPRESSED),
-      xkb_tracker_->GetSerializeMods(XKB_STATE_MODS_LOCKED),
-      xkb_tracker_->GetSerializeMods(XKB_STATE_MODS_LATCHED),
-      xkb_tracker_->GetSerializeLayout(XKB_STATE_LAYOUT_EFFECTIVE));
+      modifiers.depressed, modifiers.locked, modifiers.latched,
+      modifiers.group);
   wl_client_flush(client());
 }
 

components/exo/xkb_tracker.cc

@@ -5,6 +5,7 @@
 #include "components/exo/xkb_tracker.h"
 
 #if BUILDFLAG(USE_XKBCOMMON)
+#include "components/exo/keyboard_modifiers.h"
 #include "ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h"
 #endif
 
@@ -50,12 +51,13 @@ std::unique_ptr<char, base::FreeDeleter> XkbTracker::GetKeymap() const {
       xkb_keymap_get_as_string(xkb_keymap_.get(), XKB_KEYMAP_FORMAT_TEXT_V1));
 }
 
-uint32_t XkbTracker::GetSerializeMods(xkb_state_component components) const {
-  return xkb_state_serialize_mods(xkb_state_.get(), components);
-}
-
-uint32_t XkbTracker::GetSerializeLayout(xkb_state_component components) const {
-  return xkb_state_serialize_layout(xkb_state_.get(), components);
+KeyboardModifiers XkbTracker::GetModifiers() const {
+  return {
+      xkb_state_serialize_mods(xkb_state_.get(), XKB_STATE_MODS_DEPRESSED),
+      xkb_state_serialize_mods(xkb_state_.get(), XKB_STATE_MODS_LOCKED),
+      xkb_state_serialize_mods(xkb_state_.get(), XKB_STATE_MODS_LATCHED),
+      xkb_state_serialize_layout(xkb_state_.get(), XKB_STATE_LAYOUT_EFFECTIVE),
+  };
 }
 
 void XkbTracker::UpdateKeyboardLayoutInternal(const xkb_rule_names* names) {

components/exo/xkb_tracker.h

@@ -21,6 +21,8 @@
 
 namespace exo {
 
+struct KeyboardModifiers;
+
 // Tracks the state of XKB. If Chrome is configured not to link against
 // libxkbcommon this class is empty.
 // TODO(hidehiko): Share the state between wl_keyboard and zwp_text_input.
@@ -42,11 +44,8 @@ class XkbTracker {
   // Returns the XKB keymap data.
   std::unique_ptr<char, base::FreeDeleter> GetKeymap() const;
 
-  // Returns the current modifier state of the given components.
-  uint32_t GetSerializeMods(xkb_state_component components) const;
-
-  // Returns the current layout state of the given components.
-  uint32_t GetSerializeLayout(xkb_state_component components) const;
+  // Returns the current keyboard modifiers.
+  KeyboardModifiers GetModifiers() const;
 
  private:
   void UpdateKeyboardLayoutInternal(const xkb_rule_names* names);