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 400a2c634cd9e4bfbd14efe76266132fc45a3ce7..11adb3931788324a4fab6f7d0c4a9b9728554f7f 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 "ui/gfx/size.h"
 
@@ -24,6 +23,10 @@ namespace base {
 class DictionaryValue;
 }
 
+namespace experiments_helper {
+struct NameGroupId;
+}
+
 namespace webkit {
 struct WebPluginInfo;
 }
@@ -96,7 +99,7 @@ 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::NameGroupId>* field_trial_ids) const;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(MetricsLogTest, ChromeOSStabilityData);