Call the DisconnectWindow interface methods on the UI thread.

remoting/host/chromoting_host_unittest.cc

Index: remoting/host/chromoting_host_unittest.cc
diff --git a/remoting/host/chromoting_host_unittest.cc b/remoting/host/chromoting_host_unittest.cc
index 54df055b20090a51baac8d39ecf609924f8b129b..3e4c051649abe6f7275a7ea949dd43201cc4df67 100644
--- a/remoting/host/chromoting_host_unittest.cc
+++ b/remoting/host/chromoting_host_unittest.cc
@@ -75,12 +75,16 @@ class ChromotingHostTest : public testing::Test {
         .WillByDefault(Return(&message_loop_));
     ON_CALL(context_, network_message_loop())
         .WillByDefault(Return(&message_loop_));
+    ON_CALL(context_, ui_message_loop())
+        .WillByDefault(Return(&message_loop_));
     EXPECT_CALL(context_, main_message_loop())
         .Times(AnyNumber());
     EXPECT_CALL(context_, encode_message_loop())
         .Times(AnyNumber());
     EXPECT_CALL(context_, network_message_loop())
         .Times(AnyNumber());
+    EXPECT_CALL(context_, ui_message_loop())
+        .Times(AnyNumber());
 
     Capturer* capturer = new CapturerFake();
     event_executor_ = new MockEventExecutor();