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

chrome/browser/chromeos/system/touchpad_settings.cc

 // Copyright (c) 2011 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 "chrome/browser/chromeos/system/touchpad_settings.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/process_util.h"
 #include "base/stringprintf.h"
 #include "chrome/browser/chromeos/system/runtime_environment.h"
 #include "content/browser/browser_thread.h"
 
 namespace chromeos {
 namespace system {
 namespace touchpad_settings {
 namespace {
 const char* kTpControl = "/opt/google/touchpad/tpcontrol";
-}  // namespace
 
 // Launches the tpcontrol command asynchronously, if it exists.
 void LaunchTpControl(const std::vector<std::string>& argv) {
-  if (!system::runtime_environment::IsRunningOnChromeOS()) {
-    // Do nothing on Linux desktop, as the command does not exist.
+  if (!TouchpadExists())
     return;
-  }
-
-  if (!file_util::PathExists(FilePath(argv[0]))) {
-    LOG(ERROR) << argv[0] << " not found";
-    return;
-  }
 
   base::LaunchOptions options;
   options.wait = false;  // Launch asynchronously.
 
   base::LaunchProcess(CommandLine(argv), options, NULL);
 }
 
+}  // namespace
+
+bool TouchpadExists() {
+  // Do nothing on Linux desktop, as the command does not exist.
+  return system::runtime_environment::IsRunningOnChromeOS() &&
+      file_util::PathExists(FilePath(kTpControl));

[DaveMoore, 2011/10/13 00:04:43]

This file exists even on devices with no touchpad.

[achuithb, 2011/10/13 00:06:44]

How do you tell if there's no touchpad then?

+}
+
 void SetSensitivity(int value) {
   // Run this on the FILE thread.
   if (!BrowserThread::CurrentlyOn(BrowserThread::FILE)) {
     BrowserThread::PostTask(
         BrowserThread::FILE, FROM_HERE,
         base::Bind(&SetSensitivity, value));
     return;
   }
 
   std::vector<std::string> argv;
@@ skipping 17 matching lines @@
   argv.push_back(kTpControl);
   argv.push_back("taptoclick");
   argv.push_back(enabled ? "on" : "off");
 
   LaunchTpControl(argv);
 }
 
 }  // namespace touchpad_settings
 }  // namespace system
 }  // namespace chromeos