Fix Mojo tests crash.

FATAL:binding_state.cc(90)] Check failed: !is_bound().
Attempting to bind interface that is already bound:
  chromeos.ime.mojom.InputChannel
::TestClientChannel::CreateInterfacePtrAndBind()

Bug: 859432
Change-Id: I7b2ac928afe97b8adb1a1f89348a904d47be851b
Reviewed-on: https://chromium-review.googlesource.com/1250564Reviewed-by: Darren Shen <shend@chromium.org>
Commit-Queue: Leo Zhang <googleo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595003}

chromeos/services/ime/ime_service_unittest.cc

@@ -152,19 +152,20 @@ TEST_F(ImeServiceTest, ConnectInvalidImeEngine) {
 
 TEST_F(ImeServiceTest, MultipleClients) {
   bool success = false;
-  TestClientChannel test_channel;
+  TestClientChannel test_channel1;
+  TestClientChannel test_channel2;
   mojom::InputChannelPtr to_engine_ptr1;
   mojom::InputChannelPtr to_engine_ptr2;
 
   ime_manager_->ConnectToImeEngine(
       "m17n:ar", mojo::MakeRequest(&to_engine_ptr1),
-      test_channel.CreateInterfacePtrAndBind(), extra,
+      test_channel1.CreateInterfacePtrAndBind(), extra,
       base::BindOnce(&ConnectCallback, &success));
   ime_manager_.FlushForTesting();
 
   ime_manager_->ConnectToImeEngine(
       "m17n:ar", mojo::MakeRequest(&to_engine_ptr2),
-      test_channel.CreateInterfacePtrAndBind(), extra,
+      test_channel2.CreateInterfacePtrAndBind(), extra,
       base::BindOnce(&ConnectCallback, &success));
   ime_manager_.FlushForTesting();