Always destroy CrxInstaller on the UI Thread

extensions/browser/sandboxed_unpacker_unittest.cc

Index: extensions/browser/sandboxed_unpacker_unittest.cc
diff --git a/extensions/browser/sandboxed_unpacker_unittest.cc b/extensions/browser/sandboxed_unpacker_unittest.cc
index f85d41dd247d10e692c1a3117621f3471f4989f1..dbfee357cb4e19d872fdd9703ccddb8c1289ec5c 100644
--- a/extensions/browser/sandboxed_unpacker_unittest.cc
+++ b/extensions/browser/sandboxed_unpacker_unittest.cc
@@ -26,6 +26,9 @@ namespace extensions {
 
 class MockSandboxedUnpackerClient : public SandboxedUnpackerClient {
  public:
+  MockSandboxedUnpackerClient(const scoped_refptr<base::MessageLoopProxy>& loop)
+      : SandboxedUnpackerClient(loop) {}
+
   void WaitForUnpack() {
     scoped_refptr<content::MessageLoopRunner> runner =
         new content::MessageLoopRunner;
@@ -68,7 +71,9 @@ class SandboxedUnpackerTest : public ExtensionsTest {
     in_process_utility_thread_helper_.reset(
         new content::InProcessUtilityThreadHelper);
     // It will delete itself.
-    client_ = new MockSandboxedUnpackerClient;
+    client_ = new MockSandboxedUnpackerClient(
+        content::BrowserThread::GetMessageLoopProxyForThread(
+            content::BrowserThread::UI));
   }
 
   void TearDown() override {