[OfflinePages] Rename PRERENDERING_* result terminology to LOADING_*

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 40766c3a99f44b89ca86f7ae3e17ce503d74397c..373ce7a4ad0e29fb4f528ee5a5907e5239cf73ba 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -96313,14 +96313,14 @@ value.
   <int value="1" label="Loaded (not expected to be recorded)"/>
   <int value="2" label="Saved"/>
   <int value="3" label="RequestCoordinator canceled"/>
-  <int value="4" label="Prerendering canceled"/>
-  <int value="5" label="Prerendering failed (retryable)"/>
+  <int value="4" label="Loading canceled"/>
+  <int value="5" label="Loading failed (retryable)"/>
   <int value="6" label="Save failed"/>
   <int value="7" label="Foreground transition canceled"/>
   <int value="8" label="RequestCoordinator timed-out"/>
-  <int value="9" label="Prerendering not started"/>
-  <int value="10" label="Prerendering failed (non-retryable)"/>
-  <int value="11" label="Prerendering failed (don't start next request)"/>
+  <int value="9" label="Loading not started"/>
+  <int value="10" label="Loading failed (non-retryable)"/>
+  <int value="11" label="Loading failed (don't start next request)"/>
 </enum>
 
 <enum name="OfflinePagesCctApiPrerenderAllowedStatus" type="int">