Fix IOS.RestoreNavigationItemCount histogram name.

Follow up for http://crrev.com/c/1225697/6/ios/web/navigation/navigation_manager_impl.mm#21

R=mpearson@chromium.org

Bug: 877671
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: I390bef0562886d5f02469a184ddb6c86f3f62563
Reviewed-on: https://chromium-review.googlesource.com/1229617Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592178}

ios/web/navigation/navigation_manager_impl.mm

@@ -18,7 +18,7 @@
 
 namespace web {
 
-const char kRestoreNavigationItemCount[] = "IOSRestoreNavigationItemCount";
+const char kRestoreNavigationItemCount[] = "IOS.RestoreNavigationItemCount";
 
 NavigationManager::WebLoadParams::WebLoadParams(const GURL& url)
     : url(url),

tools/metrics/histograms/histograms.xml

@@ -38845,6 +38845,18 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="IOS.RestoreNavigationItemCount" units="rank">
+  <owner>eugenebut@chromium.org</owner>
+  <summary>
+    [iOS] The number of items Navigation Manager was requested to restore. 100
+    is logged when the number of navigation items is greater than 100. This is
+    just a requested count and actual number of restored items can be smaller.
+    Restoration is triggered in the following cases (the list is not
+    exhaustive): app cold start, remote tab was open, cookie were cleared,
+    recently closed tab was restored.
+  </summary>
+</histogram>
+
 <histogram name="IOS.SearchExtension.Action" enum="IOSSearchExtensionAction">
   <owner>olivierrobin@chromium.org</owner>
   <summary>The action selected by the user in the Search Extension.</summary>
@@ -38975,18 +38987,6 @@ uploading your change for review.
   </summary>
 </histogram>
 
-<histogram name="IOSRestoreNavigationItemCount" units="rank">
-  <owner>eugenebut@chromium.org</owner>
-  <summary>
-    [iOS] The number of items Navigation Manager was requested to restore. 100
-    is logged when the number of navigation items is greater than 100. This is
-    just a requested count and actual number of restored items can be smaller.
-    Restoration is triggered in the following cases (the list is not
-    exhaustive): app cold start, remote tab was open, cookie were cleared,
-    recently closed tab was restored.
-  </summary>
-</histogram>
-
 <histogram name="IPC.AttachmentBrokerPrivileged.BrokerAttachmentError"
     enum="IPCAttachmentBrokerPrivilegedBrokerAttachmentError">
   <owner>erikchen@chromium.org</owner>