Remove 'Enable tap-to-click' checkbox for non-touchpad devices.

chrome/browser/ui/webui/options/chromeos/system_options_handler.cc

Index: chrome/browser/ui/webui/options/chromeos/system_options_handler.cc
===================================================================
--- chrome/browser/ui/webui/options/chromeos/system_options_handler.cc	(revision 106949)
+++ chrome/browser/ui/webui/options/chromeos/system_options_handler.cc	(working copy)
@@ -20,6 +20,7 @@
 #include "chrome/browser/chromeos/dbus/dbus_thread_manager.h"
 #include "chrome/browser/chromeos/dbus/power_manager_client.h"
 #include "chrome/browser/chromeos/language_preferences.h"
+#include "chrome/browser/chromeos/system/touchpad_settings.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
@@ -35,6 +36,14 @@
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
+namespace {
+
+void TouchpadExistsFileThread(bool* exists) {
+  *exists = chromeos::system::touchpad_settings::TouchpadExists();
+}
+
+}
+
 SystemOptionsHandler::SystemOptionsHandler()
     : chromeos::CrosOptionsPageUIHandler(
         new chromeos::SystemSettingsProvider()) {
@@ -106,8 +115,19 @@
   base::FundamentalValue checked(acc_enabled);
   web_ui_->CallJavascriptFunction(
       "options.SystemOptions.SetAccessibilityCheckboxState", checked);
+
+  bool* exists = new bool;
+  BrowserThread::PostTaskAndReply(BrowserThread::FILE, FROM_HERE,
+      base::Bind(&TouchpadExistsFileThread, exists),
+      base::Bind(&SystemOptionsHandler::TouchpadExists, AsWeakPtr(), exists));
 }
 
+void SystemOptionsHandler::TouchpadExists(bool* exists) {
+  if (*exists)
+    web_ui_->CallJavascriptFunction("options.SystemOptions.showTapToClick");
+  delete exists;
+}
+
 void SystemOptionsHandler::RegisterMessages() {
   DCHECK(web_ui_);
   web_ui_->RegisterMessageCallback("accessibilityChange",