[memory-infra] Implement PollFastMemoryTotal in ProcessMetricsMemoryDumpProvider.

components/tracing/common/process_metrics_memory_dump_provider.h

Index: components/tracing/common/process_metrics_memory_dump_provider.h
diff --git a/components/tracing/common/process_metrics_memory_dump_provider.h b/components/tracing/common/process_metrics_memory_dump_provider.h
index b47bdec142b7145feaf31af18dd4a7ecaad61010..5c861c370523db7744d1478059fb8aabe9189a7d 100644
--- a/components/tracing/common/process_metrics_memory_dump_provider.h
+++ b/components/tracing/common/process_metrics_memory_dump_provider.h
@@ -33,11 +33,15 @@ class TRACING_EXPORT ProcessMetricsMemoryDumpProvider
   // MemoryDumpProvider implementation.
   bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                     base::trace_event::ProcessMemoryDump* pmd) override;
+  void PollFastMemoryTotal(uint64_t* memory_total) override;

[Primiano Tucci (use gerrit), 2016/12/13 20:02:39]

maybe give this argument a more descriptive name, dunno,
approximate_resident_bytes ?

[ssid, 2016/12/14 02:59:32]

Please note this patch depends on that.
And, this has to be addressed by
https://codereview.chromium.org/2537363003/diff/260001/base/trace_event/memor...

+  void SetFastMemoryPollingEnabled(bool enabled) override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ProcessMetricsMemoryDumpProviderTest,
                            ParseProcSmaps);
   FRIEND_TEST_ALL_PREFIXES(ProcessMetricsMemoryDumpProviderTest, DumpRSS);
+  FRIEND_TEST_ALL_PREFIXES(ProcessMetricsMemoryDumpProviderTest,
+                           TestPollFastMemoryTotal);
 
   ProcessMetricsMemoryDumpProvider(base::ProcessId process);
 
@@ -49,7 +53,11 @@ class TRACING_EXPORT ProcessMetricsMemoryDumpProvider
   static uint64_t rss_bytes_for_testing;
 
 #if defined(OS_LINUX) || defined(OS_ANDROID)
+  void ClearProcStatmFile();

[Primiano Tucci (use gerrit), 2016/12/13 20:02:39]

remove this, not defined anywhere, I guess it's a leftover

[ssid, 2016/12/14 02:59:32]

Sorry fixed.

+
   static FILE* proc_smaps_for_testing;
+
+  int proc_statm_file_;

[Primiano Tucci (use gerrit), 2016/12/13 20:02:39]

fast_polling_statm_fd_

[ssid, 2016/12/14 02:59:32]

Done.

 #endif
 
   base::ProcessId process_;