[Tentaive patch for discussion] Add Purge+Suspend metrics as UMA.

content/public/test/mock_render_process_host.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_TEST_MOCK_RENDER_PROCESS_HOST_H_
 #define CONTENT_PUBLIC_TEST_MOCK_RENDER_PROCESS_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <memory>
@@ skipping 91 matching lines @@
                                          int cdm_id) const override;
 #endif
   bool IsProcessBackgrounded() const override;
   void IncrementServiceWorkerRefCount() override;
   void DecrementServiceWorkerRefCount() override;
   void IncrementSharedWorkerRefCount() override;
   void DecrementSharedWorkerRefCount() override;
   void ForceReleaseWorkerRefCounts() override;
   bool IsWorkerRefCountDisabled() override;
   void PurgeAndSuspend() override;
+  const base::TimeTicks& GetLastPurgeAndSuspendTime() const override;
 
   // IPC::Sender via RenderProcessHost.
   bool Send(IPC::Message* msg) override;
 
   // IPC::Listener via RenderProcessHost.
   bool OnMessageReceived(const IPC::Message& msg) override;
   void OnChannelConnected(int32_t peer_pid) override;
 
   // Attaches the factory object so we can remove this object in its destructor
   // and prevent MockRenderProcessHostFacotry from deleting it.
@@ skipping 66 matching lines @@
   // for deleting all MockRenderProcessHosts that have not deleted by a test in
   // the destructor and prevent them from being leaked.
   mutable ScopedVector<MockRenderProcessHost> processes_;
 
   DISALLOW_COPY_AND_ASSIGN(MockRenderProcessHostFactory);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_MOCK_RENDER_PROCESS_HOST_H_