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

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 5051bdf019778bab30064b6b0497aad6e1255829..50d41f5c72ad5b1089801a2b8214eed6cd73e2e1 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -14,6 +14,7 @@
 
 #include "base/cancelable_callback.h"
 #include "base/macros.h"
+#include "base/memory/malloc_statistics.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ref_counted.h"
 #include "base/metrics/user_metrics_action.h"
@@ -22,6 +23,7 @@
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
+#include "content/child/child_discardable_shared_memory_manager.h"
 #include "content/child/child_thread_impl.h"
 #include "content/child/memory/child_memory_coordinator_impl.h"
 #include "content/common/content_export.h"
@@ -39,6 +41,7 @@
 #include "net/base/network_change_notifier.h"
 #include "third_party/WebKit/public/platform/WebConnectionType.h"
 #include "third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h"
+#include "third_party/WebKit/public/web/WebMemoryStatistics.h"
 #include "ui/gfx/native_widget_types.h"
 
 #if defined(OS_MACOSX)
@@ -476,6 +479,13 @@ class CONTENT_EXPORT RenderThreadImpl
   bool OnControlMessageReceived(const IPC::Message& msg) override;
   void OnProcessBackgrounded(bool backgrounded) override;
   void OnProcessPurgeAndSuspend() override;
+  void OnDumpMemoryUsage();
+
+  blink::WebMemoryStatistics blink_memory_stats_;
+  base::memory::MallocStatistics malloc_stats_;
+  ChildDiscardableSharedMemoryManager::Statistics discardable_stats_;
+  size_t v8_total_heap_usage_;
+
   void RecordAction(const base::UserMetricsAction& action) override;
   void RecordComputedAction(const std::string& action) override;