Collect field trial information from the stability file

components/browser_watcher/stability_report.proto

Index: components/browser_watcher/stability_report.proto
diff --git a/components/browser_watcher/stability_report.proto b/components/browser_watcher/stability_report.proto
index 72c8fc20c1bb15452276888be525d1d8eda3b061..db9329e0a751b09e27dc142a496f767fb2438b6d 100644
--- a/components/browser_watcher/stability_report.proto
+++ b/components/browser_watcher/stability_report.proto
@@ -148,10 +148,21 @@ message ProcessState {
   // TODO(manzagop): add experiment state.
 }
 
+// Description of a field trial or experiment that the user is currently
+// enrolled in.
+// Next id: 3
+message FieldTrial {
+  // The name of the field trial, as a 32-bit identifier.
+  optional fixed32 name_id = 1;
+
+  // The user's group within the field trial, as a 32-bit identifier.
+  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
@@ -164,4 +175,7 @@ message StabilityReport {
   //     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;
 }