Remove the hash fields from FieldTrials.

chrome/browser/metrics/metrics_log.h

Index: chrome/browser/metrics/metrics_log.h
diff --git a/chrome/browser/metrics/metrics_log.h b/chrome/browser/metrics/metrics_log.h
index b219685b3e297c4b71fb44f2b4b0b319b028e751..1732f0338da6ca84d5cb34e3550ca1b7799e6c69 100644
--- a/chrome/browser/metrics/metrics_log.h
+++ b/chrome/browser/metrics/metrics_log.h
@@ -13,7 +13,6 @@
 #include <vector>
 
 #include "base/basictypes.h"
-#include "base/metrics/field_trial.h"
 #include "chrome/common/metrics/metrics_log_base.h"
 #include "content/public/common/process_type.h"
 #include "ui/gfx/size.h"
@@ -29,6 +28,10 @@ namespace tracked_objects {
 struct ProcessDataSnapshot;
 }
 
+namespace experiments_helper {
+struct SelectedGroupId;
+}
+
 namespace webkit {
 struct WebPluginInfo;
 }
@@ -107,7 +110,7 @@ class MetricsLog : public MetricsLogBase {
   // Fills |field_trial_ids| with the list of initialized field trials name and
   // group ids.
   virtual void GetFieldTrialIds(
-    std::vector<base::FieldTrial::NameGroupId>* field_trial_ids) const;
+    std::vector<experiments_helper::SelectedGroupId>* field_trial_ids) const;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(MetricsLogTest, ChromeOSStabilityData);