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/profiled_scope.h

@@ -0,0 +1,46 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+
+#ifndef WVCDM_PROFILER_PROFILED_SCOPE_H_
+#define WVCDM_PROFILER_PROFILED_SCOPE_H_
+
+#include <stdint.h>
+
+#include "entry_writer.h"
+#include "oem_functions.h"
+
+namespace wvcdm {
+namespace oemprofiler {
+
+class ProfiledScope {
+ public:
+  explicit ProfiledScope(OEM_FUNCTION fid);
+  explicit ProfiledScope(uint32_t sid, OEM_FUNCTION fid);
+ ~ProfiledScope();
+
+  EntryWriter meta_data_;
+
+  // All profiling data must be assigned to a session but some oem
+  // crypto calls are not associated with crypto sessions. To gather
+  // those functions' data, the global session id is used. Crypto.Session
+  // Ids are unsigned 32 bit integers. To use those as a profiling session
+  // id but also allow for a global id that won't conflict with them,
+  // we use a -1 as the a proifiling session id is a signed 64 bit integer.
+  static const int64_t kGlobalSID = -1;
+
+ private:
+  int64_t sid_;
+  OEM_FUNCTION fid_;
+
+  uint64_t start_time_;
+
+  void Submit(int64_t sid, uint64_t end_time) const;
+  uint64_t GetNowUS() const;
+
+  // disallow copy and assign
+  ProfiledScope(const ProfiledScope&);
+  void operator=(const ProfiledScope&);
+};
+
+} // namespace oemprofiler
+} // namespace wvcdm
+#endif