cros: Fix a JS error and wrong kiosk log

- Fix a JS error when user presses accelerator too quickly;
- Fix a wrongly emitted kiosk launch log introduced during refactoring;

Bug: 823768
Change-Id: I432f7e1a6fc7fd62794c81aafc75ea8efcc75fd2
Reviewed-on: https://chromium-review.googlesource.com/973465Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544736}

chrome/browser/chromeos/app_mode/kiosk_profile_loader.cc

@@ -109,14 +109,13 @@ class KioskProfileLoader::CryptohomedChecker
       return;
     }
 
-    if (!is_mounted.value())
-      SYSLOG(ERROR) << "Cryptohome is mounted before launching kiosk app.";
-
     // Proceed only when cryptohome is not mounded or running on dev box.
-    if (!is_mounted.value() || !base::SysInfo::IsRunningOnChromeOS())
+    if (!is_mounted.value() || !base::SysInfo::IsRunningOnChromeOS()) {
       ReportCheckResult(KioskAppLaunchError::NONE);
-    else
+    } else {
+      SYSLOG(ERROR) << "Cryptohome is mounted before launching kiosk app.";
       ReportCheckResult(KioskAppLaunchError::ALREADY_MOUNTED);
+    }
   }
 
   void ReportCheckResult(KioskAppLaunchError::Error error) {

ui/login/display_manager.js

@@ -385,12 +385,12 @@ cr.define('cr.ui.login', function() {
      * @param {string} name Accelerator name.
      */
     handleAccelerator: function(name) {
-      if (this.currentScreen.ignoreAccelerators) {
+      if (this.currentScreen && this.currentScreen.ignoreAccelerators) {
         return;
       }
       var currentStepId = this.screens_[this.currentStep_];
       if (name == ACCELERATOR_CANCEL) {
-        if (this.currentScreen.cancel) {
+        if (this.currentScreen && this.currentScreen.cancel) {
           this.currentScreen.cancel();
         }
       } else if (name == ACCELERATOR_ENABLE_DEBBUGING) {