Switch from Delegate to Observer.

components/arc/test/fake_arc_bridge_bootstrap.h

Index: components/arc/test/fake_arc_bridge_bootstrap.h
diff --git a/components/arc/test/fake_arc_bridge_bootstrap.h b/components/arc/test/fake_arc_bridge_bootstrap.h
index 5076a0738deb828ef23342a52f3aec6c81f265d2..2e3253dcaf56b837c541504429c951acf0398966 100644
--- a/components/arc/test/fake_arc_bridge_bootstrap.h
+++ b/components/arc/test/fake_arc_bridge_bootstrap.h
@@ -9,7 +9,6 @@
 
 #include "base/macros.h"
 #include "components/arc/arc_bridge_bootstrap.h"
-#include "components/arc/test/fake_arc_bridge_instance.h"
 
 namespace arc {
 
@@ -42,7 +41,6 @@ class FakeArcBridgeBootstrap : public ArcBridgeBootstrap {
  private:
   bool boot_failure_emulation_enabled_ = false;
   ArcBridgeService::StopReason boot_failure_reason_;
-  FakeArcBridgeInstance instance_;
 
   bool boot_suspended_ = false;