arc: Revamp the ArcBridgeService interface

components/arc/metrics/arc_metrics_service.h

Index: components/arc/metrics/arc_metrics_service.h
diff --git a/components/arc/metrics/arc_metrics_service.h b/components/arc/metrics/arc_metrics_service.h
index 4f611787a280051268a6672f7880a0ccc4952347..25f38ef1a08fa69d83b2d9b42489a0825a914335 100644
--- a/components/arc/metrics/arc_metrics_service.h
+++ b/components/arc/metrics/arc_metrics_service.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_ARC_METRICS_ARC_METRICS_SERVICE_H
-#define COMPONENTS_ARC_METRICS_ARC_METRICS_SERVICE_H
+#ifndef COMPONENTS_ARC_METRICS_ARC_METRICS_SERVICE_H_
+#define COMPONENTS_ARC_METRICS_ARC_METRICS_SERVICE_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
@@ -18,18 +18,22 @@
 namespace arc {
 
 // Collects information from other ArcServices and send UMA metrics.
-class ArcMetricsService : public ArcService,
-                          public ArcBridgeService::Observer,
-                          public mojom::MetricsHost {
+class ArcMetricsService
+    : public ArcService,
+      public ArcBridgeService::InstanceObserver<mojom::MetricsInstance>,
+      public ArcBridgeService::InstanceObserver<mojom::ProcessInstance>,
+      public mojom::MetricsHost {
  public:
   explicit ArcMetricsService(ArcBridgeService* bridge_service);
   ~ArcMetricsService() override;
 
-  // ArcBridgeService::Observer overrides.
-  void OnMetricsInstanceReady() override;
-  void OnMetricsInstanceClosed() override;
-  void OnProcessInstanceReady() override;
-  void OnProcessInstanceClosed() override;
+  // ArcBridgeService::InstanceObserver<mojom::MetricsInstance> overrides.
+  void OnInstanceReady(mojom::MetricsInstance*, uint32_t version) override;
+  void OnInstanceClosed(mojom::MetricsInstance*) override;
+
+  // ArcBridgeService::InstanceObserver<mojom::ProcessInstance> overrides.
+  void OnInstanceReady(mojom::ProcessInstance*, uint32_t version) override;
+  void OnInstanceClosed(mojom::ProcessInstance*) override;
 
   // MetricsHost overrides.
   void ReportBootProgress(
@@ -63,4 +67,4 @@ class ArcMetricsService : public ArcService,
 
 }  // namespace arc
 
-#endif  // COMPONENTS_ARC_METRICS_ARC_METRICS_SERVICE_H
+#endif  // COMPONENTS_ARC_METRICS_ARC_METRICS_SERVICE_H_