cocoa: add experimental tabstrip keyboard focus support

chrome/browser/ui/cocoa/tabs/tab_view.mm

 // Copyright (c) 2012 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 "chrome/browser/ui/cocoa/tabs/tab_view.h"
 
+#include "base/command_line.h"
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/themes/theme_properties.h"
 #include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/ui/cocoa/l10n_util.h"
 #import "chrome/browser/ui/cocoa/tabs/alert_indicator_button_cocoa.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_window_controller.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
 #import "chrome/browser/ui/cocoa/view_id_util.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/grit/theme_resources.h"
 #include "skia/ext/skia_utils_mac.h"
 #import "third_party/google_toolbox_for_mac/src/AppKit/GTMFadeTruncatingTextFieldCell.h"
 #import "ui/base/cocoa/nsgraphics_context_additions.h"
 #import "ui/base/cocoa/nsview_additions.h"
 #include "ui/base/cocoa/three_part_image.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 #include "ui/strings/grit/ui_strings.h"
 
 namespace {
 
 // The color of the icons in dark mode theme.
 const SkColor kDarkModeIconColor = SkColorSetARGB(0xFF, 0xC4, 0xC4, 0xC4);
 
+bool IsTabStripKeyboardFocusEnabled() {
+  return base::FeatureList::IsEnabled(features::kTabStripKeyboardFocus);
+}
+
 }  // namespace
 
 // The amount of time in seconds during which each type of glow increases, holds
 // steady, and decreases, respectively.
 const NSTimeInterval kHoverShowDuration = 0.2;
 const NSTimeInterval kHoverHoldDuration = 0.02;
 const NSTimeInterval kHoverHideDuration = 0.4;
 const NSTimeInterval kAlertShowDuration = 0.4;
 const NSTimeInterval kAlertHoldDuration = 0.4;
 const NSTimeInterval kAlertHideDuration = 0.4;
@@ skipping 736 matching lines @@
 // ThemedWindowDrawing implementation.
 
 - (void)windowDidChangeTheme {
   [self setNeedsDisplay:YES];
 }
 
 - (void)windowDidChangeActive {
   [self setNeedsDisplay:YES];
 }
 
+- (BOOL)acceptsFirstResponder {
+  return IsTabStripKeyboardFocusEnabled() ? YES : NO;
+}
+
+- (BOOL)becomeFirstResponder {
+  return IsTabStripKeyboardFocusEnabled() ? YES : NO;
+}
+
+- (void)drawFocusRingMask {
+  if (!IsTabStripKeyboardFocusEnabled())
+    return;
+  if ([titleView_ isHidden])
+    NSRectFill([self bounds]);
+  else
+    NSRectFill([titleView_ frame]);
+}
+
+- (NSRect)focusRingMaskBounds {
+  return [self bounds];
+}
+
 @end  // @implementation TabView
 
 @implementation TabView (TabControllerInterface)
 
 - (void)setController:(TabController*)controller {
   controller_ = controller;
 }
 
 @end  // @implementation TabView (TabControllerInterface)
 
@@ skipping 223 matching lines @@
 
 // For "Increase Contrast" mode, use flat black instead of semitransparent black
 // for the tab edge stroke.
 + (void)setTabEdgeStrokeColor {
   static NSColor* heavyStrokeColor =
       [skia::SkColorToSRGBNSColor(SK_ColorBLACK) retain];
   [heavyStrokeColor set];
 }
 
 @end