Metrics provider for statistical stack profiler

components/metrics/proto/call_stack_profile.proto

Index: components/metrics/proto/call_stack_profile.proto
diff --git a/components/metrics/proto/call_stack_profile.proto b/components/metrics/proto/call_stack_profile.proto
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+// Copyright 2015 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.
+
+// Call stack sample data for a given profiling session.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package metrics;
+
+// Next tag: 5
+message CallStackProfile {
+  // Describes an entry in the callstack.
+  message Entry {
+    // Instruction pointer subtracted by module base.
+    optional uint64 address = 1;
+
+    // Index to the module identifier in |module_ids| of CallStackProfile.
+    optional int32 module_id_index = 2;
+  }
+
+  // A sample consisting of one or more callstacks with the same stack frames
+  // and instruction pointers.
+  message Sample {
+    // The callstack. Sample.entries[0] represents the call on the top of the
+    // stack.
+    repeated Entry entry = 1;
+
+    // Number of times this stack signature occurs.
+    optional int64 count = 2;
+  }
+
+  // Uniquely identifies a module.
+  message ModuleIdentifier {
+    // A hash that uniquely identifies a particular program version with high
+    // probability. This is parsed from headers of the loaded module.
+    // For binaries generated by GNU tools:
+    //   Contents of the .note.gnu.build-id field.
+    // On Windows:
+    //   GUID + AGE in the debug image headers of a module.
+    optional bytes build_id = 1;
+
+    // MD5Sum Prefix of the module name. This is the same hashing scheme as used
+    // to hash UMA histogram names.
+    optional fixed64 name_md5_prefix = 2;
+  }
+
+  // The callstack and counts.
+  repeated Sample sample = 1;
+
+  // List of module ids found in this sample.
+  repeated ModuleIdentifier module_id = 2;
+
+  // Duration of this profile.
+  optional int32 profile_duration_ms = 3;
+
+  // Time between samples.
+  optional int32 sampling_period_ms = 4;
+}