MacViews: Implement Full Keyboard Access.

ui/base/test/scoped_fake_full_keyboard_access.mm

+// Copyright 2016 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.
+
+#import "ui/base/test/scoped_fake_full_keyboard_access.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/logging.h"
+#import "base/mac/scoped_objc_class_swizzler.h"
+
+namespace {
+
+ui::test::ScopedFakeFullKeyboardAccess* g_instance = nullptr;
+
+}  // namespace
+
+// Donates a testing implementation of [NSApp isFullKeyboardAccessEnabled].
+@interface FakeNSAppKeyboardAccessDonor : NSObject
+@end
+
+@implementation FakeNSAppKeyboardAccessDonor
+
+- (BOOL)isFullKeyboardAccessEnabled {
+  DCHECK(g_instance);
+  return g_instance->full_keyboard_access_state();
+}
+
+@end
+
+namespace ui {
+namespace test {
+
+ScopedFakeFullKeyboardAccess::ScopedFakeFullKeyboardAccess()
+    : full_keyboard_access_state_(true),
+      swizzler_(new base::mac::ScopedObjCClassSwizzler(
+          [NSApplication class],
+          [FakeNSAppKeyboardAccessDonor class],
+          @selector(isFullKeyboardAccessEnabled))) {
+  DCHECK(!g_instance)
+      << "Cannot initialize ScopedFakeFullKeyboardAccess twice\n";
+  g_instance = this;
+}
+
+ScopedFakeFullKeyboardAccess::~ScopedFakeFullKeyboardAccess() {
+  DCHECK_EQ(g_instance, this);
+  g_instance = nullptr;
+}
+
+// static
+ScopedFakeFullKeyboardAccess* ScopedFakeFullKeyboardAccess::GetInstance() {
+  return g_instance;
+}
+
+}  // namespace test
+}  // namespace ui