mac: use NSUserDefaults values for caret blink rate if present

The main use of these by end-users is to disable cursor blink by setting them
to extremely large values.

BUG=500168

Review-Url: https://codereview.chromium.org/2282533002
Cr-Commit-Position: refs/heads/master@{#414752}

chrome/browser/renderer_preferences_util.cc

@@ -26,6 +26,10 @@
 #include "ui/views/controls/textfield/textfield.h"
 #endif
 
+#if defined(OS_MACOSX)
+#include "ui/base/cocoa/defaults_utils.h"
+#endif
+
 #if defined(USE_AURA) && defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/themes/theme_service_factory.h"
@@ -120,6 +124,12 @@ void UpdateFromSystemSettings(content::RendererPreferences* prefs,
   prefs->caret_blink_interval = views::Textfield::GetCaretBlinkMs() / 1000.0;
 #endif
 
+#if defined(OS_MACOSX)
+  base::TimeDelta interval;
+  if (ui::TextInsertionCaretBlinkPeriod(&interval))
+    prefs->caret_blink_interval = interval.InSecondsF();
+#endif
+
 #if defined(USE_AURA) && defined(OS_LINUX) && !defined(OS_CHROMEOS)
   views::LinuxUI* linux_ui = views::LinuxUI::instance();
   if (linux_ui) {

ui/base/BUILD.gn

@@ -96,6 +96,8 @@ component("base") {
     "cocoa/controls/hyperlink_button_cell.mm",
     "cocoa/controls/hyperlink_text_view.h",
     "cocoa/controls/hyperlink_text_view.mm",
+    "cocoa/defaults_utils.h",
+    "cocoa/defaults_utils.mm",
     "cocoa/find_pasteboard.h",
     "cocoa/find_pasteboard.mm",
     "cocoa/flipped_view.h",

ui/base/cocoa/defaults_utils.h

+// 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.
+
+#ifndef UI_BASE_COCOA_DEFAULTS_UTILS_H_
+#define UI_BASE_COCOA_DEFAULTS_UTILS_H_
+
+#include "base/time/time.h"
+#include "ui/base/ui_base_export.h"
+
+namespace ui {
+
+// Returns the text insertion caret blink period, if one is configured in
+// NSUserDefaults.
+UI_BASE_EXPORT bool TextInsertionCaretBlinkPeriod(base::TimeDelta* period);
+
+}
+
+#endif

ui/base/cocoa/defaults_utils.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.
+
+#include <AppKit/AppKit.h>
+
+#include "base/logging.h"
+#include "ui/base/cocoa/defaults_utils.h"
+
+namespace ui {
+
+bool TextInsertionCaretBlinkPeriod(base::TimeDelta* delta) {
+  const int kMaximumReasonableIntervalMs = 60 * 1000;
+  NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
+  // 10.10+
+  double on_period_ms = [defaults
+      doubleForKey:@"NSTextInsertionPointBlinkPeriodOn"];
+  double off_period_ms = [defaults
+      doubleForKey:@"NSTextInsertionPointBlinkPeriodOff"];
+  // 10.9
+  double period_ms = [defaults
+      doubleForKey:@"NSTextInsertionPointBlinkPeriod"];
+  if (on_period_ms == 0.0 && off_period_ms == 0.0 && period_ms == 0.0)
+    return false;
+  // Neither Blink nor Views support having separate on and off intervals, so
+  // this function takes the average. There's a special case: setting
+  // on_period_ms very high functions to permanently enable the cursor, which is
+  // what happens when the blink period in Blink/Views is set to 0. Setting
+  // off_period_ms very high would disable the cursor entirely, but Blink/Views
+  // do not support that so it's not implemented here.
+  if (on_period_ms > kMaximumReasonableIntervalMs ||
+      period_ms > kMaximumReasonableIntervalMs) {
+    *delta = base::TimeDelta();
+  } else if (on_period_ms || off_period_ms) {
+    *delta = base::TimeDelta::FromMillisecondsD(
+        (on_period_ms + off_period_ms) / 2);
+  } else {
+    *delta = base::TimeDelta::FromMilliseconds(period_ms);
+  }
+  return true;
+}
+
+}  // namespace ui