Always destroy CrxInstaller on the UI Thread

chrome/browser/chromeos/app_mode/kiosk_app_data.cc

Index: chrome/browser/chromeos/app_mode/kiosk_app_data.cc
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_data.cc b/chrome/browser/chromeos/app_mode/kiosk_app_data.cc
index 5245aad495940b703167993d63812f8453df3f6a..afacf96955cd648c516a6dc94b6bf1b635fc5877 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_data.cc
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_data.cc
@@ -92,10 +92,12 @@ class KioskAppData::CrxLoader : public extensions::SandboxedUnpackerClient {
  public:
   CrxLoader(const base::WeakPtr<KioskAppData>& client,
             const base::FilePath& crx_file)
-      : client_(client),
+      : SandboxedUnpackerClient(
+            content::BrowserThread::GetMessageLoopProxyForThread(
+                content::BrowserThread::UI)),
+        client_(client),
         crx_file_(crx_file),
-        success_(false) {
-  }
+        success_(false) {}
 
   void Start() {
     base::SequencedWorkerPool* pool = BrowserThread::GetBlockingPool();