Settings reset prompt: add more UI metrics.

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 cd3b6aa443b104aa05784f81d3a4678e95b541f8..ff996cc2fcfe5154969fcc343ffdb45ee67cc68b 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -65230,7 +65230,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <owner>alito@chromium.org</owner>
   <summary>
     The time between the settings reset prompt dialog being shown and the user
-    declining the prompt.
+    declining the prompt by clicking the cancel button.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.TimeUntilDismissed" units="ms">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    The time between the settings reset prompt dialog being shown and the user
+    dismissing the prompt, for example by clicking on the 'x' in the dialog or
+    pressing the Escape key.
   </summary>
 </histogram>