[UMA] Include field trial tuples in the UMA upload.

chrome/common/metrics/metrics_log_base.h

Index: chrome/common/metrics/metrics_log_base.h
diff --git a/chrome/common/metrics/metrics_log_base.h b/chrome/common/metrics/metrics_log_base.h
index 3c493dd70f8448f60c73306aa869bf51aa6b8f30..8c5d5e0fc88781d26930b73cb62d754add98dd72 100644
--- a/chrome/common/metrics/metrics_log_base.h
+++ b/chrome/common/metrics/metrics_log_base.h
@@ -104,6 +104,7 @@ class MetricsLogBase {
 
   // Returns a string containing the current time.
   // Virtual so that it can be overridden for testing.
+  // TODO(isherman): Remove this method once the XML pipeline is old news.
   virtual std::string GetCurrentTimeString();
   // Helper class that invokes StartElement from constructor, and EndElement
   // from destructor.
@@ -147,6 +148,17 @@ class MetricsLogBase {
   // Write the attributes that are common to every metrics event type.
   void WriteCommonEventAttributes();
 
+  bool locked() const { return locked_; }
+
+  metrics::ChromeUserMetricsExtension* uma_proto() { return &uma_proto_; }

[jar (doing other things), 2012/03/01 05:32:42]

This is a scary interface. Why do other folks need to know where you keep your
slot?

[Ilya Sherman, 2012/03/01 06:41:50]

This method has protected visibility -- only MetricsLog gets to peek into this
implementation detail.  (Well, ok, testing classes theoretically could peek in
as well, but I don't see a clean way to avoid that.)

+  const metrics::ChromeUserMetricsExtension& uma_proto() const {

[jar (doing other things), 2012/03/01 05:32:42]

This seems a bit confusing to me, as you have overloaded based on the const-ness
of the instance, but then returned different  values.  I'd expect this will be
confusing (surprising?) when used, as the const-ness is often not locally
apparent at the call site.  i.e., sometimes you could say:
uma_proto().blah
other times:
uma_proto()->blah

[Ilya Sherman, 2012/03/01 06:41:50]

Fair enough, updated this to be a pointer as well.

+    return uma_proto_;
+  }
+
+  // TODO(isherman): Remove this once the XML pipeline is outta here.
+  int num_events_;  // the number of events recorded in this log
+
+ private:
   base::Time start_time_;
   base::Time end_time_;
 
@@ -162,12 +174,9 @@ class MetricsLogBase {
   // Isolated to limit the dependency on the XML library for our consumers.
   XmlWrapper* xml_wrapper_;
 
-  int num_events_;  // the number of events recorded in this log
-
   // Stores the protocol buffer representation for this log.
   metrics::ChromeUserMetricsExtension uma_proto_;
 
- private:
   DISALLOW_COPY_AND_ASSIGN(MetricsLogBase);
 };