Replace Dialog.Delegate.Creation with Dialog.DialogDelegate.Create.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 06a009aa8a22bf2b160a27ebc4deedaaf99fbd8d..8cf4e69b0ce155ab98b0cb7a212d02cd89968297 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -11925,6 +11925,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Dialog.Delegate.Creation" enum="BooleanCreated">
+  <obsolete>

[msw, 2017/05/12 01:34:49]

What's the real deal with deprecating versus deleting these metrics? Do we
really need the old data to live in perpetuity? If someone [maliciously]
committed a million new metrics, would we never be able to remove those entries
from this file? It's mildly irritating how ridiculous this file is...

[jwd, 2017/05/12 20:00:24]

The reason to not delete is to preserve the mapping from histogram name to hash
so that old data is still readable (we treat this file as the ground truth). In
the case of the malicious or erroneous addition of a million metrics, we would
just remove them no big deal.

In this case, I'd almost suggest just deleting it, but it's made it to dev. If
we want to have a look at the dev data, we should keep it in, as obsolete. If
not, then I'm fine removing it entirely.

And note, the metrics team is aware of how ridiculous this file is, improving it
is always on our radar.

+    Deprecated, use Dialog.DialogDelegate.Create.
+  </obsolete>
   <owner>pdyson@chromium.org</owner>
   <summary>
     Counts the number times dialog boxes are created using DialogDelegate.
@@ -85480,6 +85483,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram_suffixes>
 
 <histogram_suffixes name="DialogTypes" separator="." ordering="prefix">
+  <suffix name="DialogDelegate"
+      label="Counts dialog boxes created using DialogDelegate."/>
   <suffix name="DialogDelegateView"
       label="Counts dialog boxes created using DialogDelegateView. These are
              a subset of those created with DialogDelegate."/>