Implementing sign-in promo histograms for settings

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 a4dd09acd35abca4d5afc02a37f004c0b310ab7a..d98d73d72b14aefc60750d168b625da705d53df1 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -32743,7 +32743,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <owner>jlebel@chromium.org</owner>
   <summary>
     Counts how many times the signin promo is implicitly dismissed (by closing
-    the bookmark manager) per impression.
+    the bookmark manager) per impression, only iOS.
   </summary>
 </histogram>
 
@@ -32754,7 +32754,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     Counts how many times one of the &quot;sign in&quot; buttons (any of the
     signed-out &quot;Sign in to Chrome&quot; button, the &quot;Continue as
     |name|&quot; button, or the &quot;Not |email|?&quot; button) is clicked per
-    impression.
+    impression, only iOS.
   </summary>
 </histogram>
 
@@ -32763,7 +32763,27 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <owner>jlebel@chromium.org</owner>
   <summary>
     Counts how many times the explicit &quot;X&quot;-to-close button is clicked
-    per impression.
+    per impression, only iOS.
+  </summary>
+</histogram>
+
+<histogram name="MobileSignInPromo.SettingsManager.ImpressionsTilDismiss"
+    units="impressions">
+  <owner>jlebel@chromium.org</owner>
+  <summary>
+    Counts how many times the signin promo is implicitly dismissed (by closing
+    the settings view) per impression, only iOS.
+  </summary>
+</histogram>
+
+<histogram name="MobileSignInPromo.SettingsManager.ImpressionsTilSigninButtons"
+    units="impressions">
+  <owner>jlebel@chromium.org</owner>
+  <summary>
+    Counts how many times one of the &quot;sign in&quot; buttons (any of the
+    signed-out &quot;Sign in to Chrome&quot; button, the &quot;Continue as
+    |name|&quot; button, or the &quot;Not |email|?&quot; button) is clicked per
+    impression, only iOS.
   </summary>
 </histogram>