Collect field trial information from the stability file

components/browser_watcher/stability_report.proto

 // Copyright 2016 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 browser_watcher;
 
@@ skipping 132 matching lines @@
   // The identifier of the process.
   optional int64 process_id = 3;
 
   // Note: likely only a subset of modules of interest (e.g. Chromium's own
   // modules).
   repeated CodeModule modules = 1;
   repeated ThreadState threads = 2;
   // TODO(manzagop): add experiment state.
 }
 
+// Description of a field trial or experiment that the user is currently
+// enrolled in. This message is an analogue of the UMA proto in
+// components/metrics/proto/system_profile.proto. For details about generating
+// the identifiers from the field trial and group names, see
+// variations::MakeActiveGroupId().
+// Next id: 3
+message FieldTrial {
+  // A 32-bit identifier for the name of the field trial.
+  optional fixed32 name_id = 1;
+
+  // A 32-bit identifier for the user's group within the field trial.
+  optional fixed32 group_id = 2;
+}
+
 // A stability report contains information pertaining to the execution of a
 // single logical instance of a "chrome browser". It is comprised of information
 // about the system state and about the chrome browser's processes.
-// Next id: 5
+// Next id: 6
 message StabilityReport {
   optional SystemState system_state = 1;
   // TODO(manzagop): revisit whether a single repeated field should contain all
   //     processes, or whether it's preferable to have separate fields per type.
   // TODO(manzagop): add information about the type of process, pid, process
   //     times (e.g. start time), hierarchical relationships (e.g. parent pid),
   //     command line, etc.
   repeated ProcessState process_states = 2;
   // TODO(manzagop): if/when reports contain multiple processes, attribute and
   //     relocate these to their process (and perhaps thread).
   repeated string log_messages = 3;
   map<string, TypedValue> global_data = 4;
+
+  // The field trials the user is currently enrolled in.
+  repeated FieldTrial field_trials = 5;
 }