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

content/public/test/mock_render_process_host.cc

Index: content/public/test/mock_render_process_host.cc
diff --git a/content/public/test/mock_render_process_host.cc b/content/public/test/mock_render_process_host.cc
index 6d20cc65a6f08ea4a5aaabc1da47ae90ebaabc86..8f25c90c613f3df812082a9a983240a44370e70d 100644
--- a/content/public/test/mock_render_process_host.cc
+++ b/content/public/test/mock_render_process_host.cc
@@ -312,6 +312,12 @@ bool MockRenderProcessHost::IsWorkerRefCountDisabled() {
 
 void MockRenderProcessHost::PurgeAndSuspend() {}
 
+const base::TimeTicks& MockRenderProcessHost::GetLastPurgeAndSuspendTime()
+    const {
+  static base::TimeTicks dummy_time = base::TimeTicks::Now();
+  return dummy_time;
+}
+
 void MockRenderProcessHost::FilterURL(bool empty_allowed, GURL* url) {
   RenderProcessHostImpl::FilterURL(this, empty_allowed, url);
 }