Introduce ServiceWorker.MainFramePageLoad.CoreTransition and RedirectChainLength UMAs.

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 2b4c1893ea6f974961797557c45edde4e7ae75ee..212861ac198d41ecbabc43e56be1b7578423bfd1 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -48689,8 +48689,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="Prerender.LocalVisitCoreTransition"
-    enum="PrerenderLocalVisitCoreTransition">
+<histogram name="Prerender.LocalVisitCoreTransition" enum="CorePageTransition">
   <obsolete>
     deprecated Nov 16 2012
   </obsolete>
@@ -58495,6 +58494,24 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="ServiceWorker.MainFramePageLoad.CoreTransition"
+    enum="CorePageTransition">
+  <owner>horo@chromium.org</owner>
+  <summary>
+    The transition type for main frame page loads controlled by a service
+    worker.
+  </summary>
+</histogram>
+
+<histogram name="ServiceWorker.MainFramePageLoad.RedirectChainLength"
+    units="urls">
+  <owner>horo@chromium.org</owner>
+  <summary>
+    Total length of the server redirects during main frame page loads controlled
+    by a service worker.
+  </summary>
+</histogram>
+
 <histogram name="ServiceWorker.MessageEvent.Time" units="ms">
   <obsolete>
     Deprecated 2016-04 in favor of ServiceWorker.ExtendableMessageEvent.Time.
@@ -79849,6 +79866,23 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="7" label="First-Party-Only, HttpOnly, Secure"/>
 </enum>
 
+<enum name="CorePageTransition" type="int">
+  <summary>
+    The core value of PageTransition. See ui/base/page_transition_types.h.
+  </summary>
+  <int value="0" label="LINK"/>
+  <int value="1" label="TYPED"/>
+  <int value="2" label="AUTO_BOOKMARK"/>
+  <int value="3" label="AUTO_SUBFRAME"/>
+  <int value="4" label="MANUAL_SUBFRAME"/>
+  <int value="5" label="GENERATED"/>
+  <int value="6" label="START_PAGE"/>
+  <int value="7" label="FORM_SUBMIT"/>
+  <int value="8" label="RELOAD"/>
+  <int value="9" label="KEYWORD"/>
+  <int value="10" label="KEYWORD_GENERATED"/>
+</enum>
+
 <enum name="CorruptExtensionDisabledReason" type="int">
   <summary>
     The reason why content verification flagged an extension as corrupted. See
@@ -98482,23 +98516,6 @@ value.
   <int value="95" label="Issue Prerender prefetch issued"/>
 </enum>
 
-<enum name="PrerenderLocalVisitCoreTransition" type="int">
-  <obsolete>
-    Deprecated Nov 16 2012
-  </obsolete>
-  <int value="0" label="LINK"/>
-  <int value="1" label="TYPED"/>
-  <int value="2" label="AUTO_BOOKMARK"/>
-  <int value="3" label="AUTO_SUBFRAME"/>
-  <int value="4" label="MANUAL_SUBFRAME"/>
-  <int value="5" label="GENERATED"/>
-  <int value="6" label="START_PAGE"/>
-  <int value="7" label="FORM_SUBMIT"/>
-  <int value="8" label="RELOAD"/>
-  <int value="9" label="KEYWORD"/>
-  <int value="10" label="GENERATED"/>
-</enum>
-
 <enum name="PrerenderLocalVisitEvents" type="int">
   <obsolete>
     Deprecated Nov 16 2012