Revert of arc: Use the new InstanceHolder for unittests

components/arc/test/fake_app_instance.cc

Index: components/arc/test/fake_app_instance.cc
diff --git a/components/arc/test/fake_app_instance.cc b/components/arc/test/fake_app_instance.cc
index 64822b753a92bead33f4e07fe6eb441e5bb39514..919d3937ebe10d6a669c0dccc193f8401526716a 100644
--- a/components/arc/test/fake_app_instance.cc
+++ b/components/arc/test/fake_app_instance.cc
@@ -38,7 +38,7 @@
 namespace arc {
 
 FakeAppInstance::FakeAppInstance(mojom::AppHost* app_host)
-    : app_host_(app_host) {}
+    : binding_(this), app_host_(app_host) {}
 FakeAppInstance::~FakeAppInstance() {}
 
 void FakeAppInstance::RefreshAppList() {
@@ -166,6 +166,25 @@
   app_host_->OnPackageRemoved(package_name);
 }
 
+void FakeAppInstance::WaitForIncomingMethodCall() {
+  binding_.WaitForIncomingMethodCall();
+}
+
+void FakeAppInstance::WaitForOnAppInstanceReady() {
+  // Several messages are sent back and forth when OnAppInstanceReady() is
+  // called. Normally, it would be preferred to use a single
+  // WaitForIncomingMethodCall() to wait for each method individually, but
+  // QueryVersion() does require processing on the I/O thread, so
+  // RunUntilIdle() is required to correctly dispatch it. On slower machines
+  // (and when running under Valgrind), the two thread hops needed to send and
+  // dispatch each Mojo message might not be picked up by a single
+  // RunUntilIdle(), so keep pumping the message loop until all expected
+  // messages are.
+  while (refresh_app_list_count_ != 1) {
+    base::RunLoop().RunUntilIdle();
+  }
+}
+
 void FakeAppInstance::CanHandleResolution(
     const mojo::String& package_name,
     const mojo::String& activity,