Add a SetCanonicalCookie method for CookieMonster.

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 5531120f8916006dd7d143958ad9dc20edfb00d8..77deb73eaca3e2631728fcba097acd6e39f6a201 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -8985,6 +8985,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Cookie.CookieSourceScheme" enum="CookieSourceScheme">
+  <obsolete>
+    Replaced by Cookie.CookieSourceScheme2.
+  </obsolete>
   <owner>estark@chromium.org</owner>
   <summary>
     For each cookie added to the store, record whether its source URL has a
@@ -8992,6 +8995,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Cookie.CookieSourceScheme2" enum="CookieSourceScheme">
+  <owner>estark@chromium.org</owner>
+  <summary>
+    For each cookie added to the store, record whether its source URL has a
+    cryptographic scheme, broken down by Secure and not Secure. Cookies added to
+    the store unassociated with an origin will be considered to not have a
+    cryptographic scheme.
+  </summary>
+</histogram>
+
 <histogram name="Cookie.CorruptMetaTable">
   <owner>tnagel@chromium.org</owner>
   <summary>