Add new SampledProfile protobuf definition

chrome/common/metrics/proto/profile_collection.proto

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package metrics;
+
+import "perf_data.proto";
+
+// Protocol buffer for collected profiling data.
+// Contains the parameters and data from a single profile collection event.
+
+// Next tag: 6
+message ProfileCollection {
+  // Indicates the event that triggered this collection.
+  enum TriggerType {
+    UNKNOWN = 0;
+    PERIODIC = 1;     // Collect at a random point within periodic intervals.
+  }
+  optional TriggerType trigger_type = 1;
+
+  // The type of profile data that was collected.
+  enum ProfileType {
+    PERF = 0;         // Perf profile.

[tipp, 2014/04/08 21:19:41]

Make UNKNOWN=0 and PERF=1

[Simon Que, 2014/04/08 22:57:44]

When would we use the unknown enum? We can always determine it from which
profile field is set.

[tipp, 2014/04/08 23:31:46]

#5 from http://go/protodosdonts

+  }
+  optional ProfileType profile_type = 2;
+
+  // The actual perf data that was collected, if this is a perf profile.
+  optional PerfDataProto perf_data = 3;
+
+  // Time after system boot when the collection took place.
+  optional int64 ms_after_boot = 4;
+
+  // Time after last login when the collection took place.
+  optional int64 ms_after_login = 5;
+
+  // For interval-based collections, the length of each interval.
+  optional int64 interval_period_ms = 6;
+}