OEMCrypto Profiler

This CL is a merge from the widevine repo of:
http://go/wvgerrit/16491 Circular Buffer
http://go/wvgerrit/16512 Circular Buffer Tests
http://go/wvgerrit/16493 Entry Writer
http://go/wvgerrit/16495 Profiled Scope
http://go/wvgerrit/16500 Stats Collection
http://go/wvgerrit/16543 Disallow Stats Copy or Assign
http://go/wvgerrit/16514 Moving OEM Function Enum
http://go/wvgerrit/16501 Defining Session Interface
http://go/wvgerrit/16502 Session Definitions
http://go/wvgerrit/16573 Remove code to num bytes table
http://go/wvgerrit/16556 Connecting Profiler to Profiled Scope
http://go/wvgerrit/16557 Android Reading Profiler History
http://go/wvgerrit/16574 Adding Get Stats Method
http://go/wvgerrit/16606 Seperating Session Parsing
http://go/wvgerrit/16607 Adding get stats method to DRMPlugin
http://go/wvgerrit/16608 Fixing Linux Build Failure
http://go/wvgerrit/16612 Stop Clearing History
http://go/wvgerrit/16613 Accessing profiler information using session id
http://go/wvgerrit/16614 Making All Session Subsets of Global Session

BUG: 25123303
BUG: 26027857
Change-Id: Ie2422e644aa631871852ea0e461695aeb7060f88

libwvdrmengine/cdm/profiler/include/stats.h

@@ -0,0 +1,40 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+
+#ifndef WVCDM_PROFILER_STATS_H_
+#define WVCDM_PROFILER_STATS_H_
+
+#include <stdint.h>
+
+namespace wvcdm {
+namespace oemprofiler {
+
+class Stat {
+ public:
+  Stat();
+
+  void Update(uint64_t sample);
+  void Reset();
+
+  uint64_t GetMin() const;
+  uint64_t GetMax() const;
+  uint64_t GetSampleSize() const;
+  double GetMean() const;
+  double GetVariance() const;
+
+ private:
+  uint64_t min_;
+  uint64_t max_;
+  double mean_;
+  uint64_t count_;
+
+  double sdev_m_;
+  double sdev_s_;
+
+  Stat(const Stat&);
+  void operator=(const Stat&);
+};
+
+}    // namespace oemprofiler
+}    // namespace wvcdm
+
+#endif