Adding basic Metro Print Metrics.

printing/printing_context_win.cc

Index: printing/printing_context_win.cc
diff --git a/printing/printing_context_win.cc b/printing/printing_context_win.cc
index 99f92cb3be0005305e7b4ea6865b8db8932a16a8..522da3d687913fa37836477d81bdc33c9135669e 100644
--- a/printing/printing_context_win.cc
+++ b/printing/printing_context_win.cc
@@ -11,6 +11,7 @@
 #include "base/i18n/file_util_icu.h"
 #include "base/i18n/time_formatting.h"
 #include "base/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
@@ -230,8 +231,12 @@ void PrintingContextWin::AskUserForSettings(
       MetroShowPrintUI metro_show_print_ui =
           reinterpret_cast<MetroShowPrintUI>(
               ::GetProcAddress(metro_module, "MetroShowPrintUI"));
-      if (metro_show_print_ui)
+      if (metro_show_print_ui) {
+        // TODO(mad): Remove this once we can send user metrics from the metro
+        // driver. crbug.com/142330
+        UMA_HISTOGRAM_ENUMERATION("Metro.Print", 1, 2);

[Ilya Sherman, 2012/08/13 22:34:00]

nit: I recommend having a single location in the codebase that logs any given
histogram.  Typically, I've seen people create small utility
header+implementation files for this purpose.  The advantages are (1) it's much
less likely that you'll accidentally name the histogram differently in different
call sites due to a typo; (2) you can't forget to update one of the call sites
when updating the histogram; and (3) Jim tells me we end up with slightly better
compiled code if there's only one definition for each histogram (this last
reason is pretty minor though).

         metro_show_print_ui();
+      }
     }
     return callback.Run(CANCEL);
   }