Report frequency of single page app navigations to UMA

third_party/WebKit/Source/core/loader/FrameLoaderTypes.h

Index: third_party/WebKit/Source/core/loader/FrameLoaderTypes.h
diff --git a/third_party/WebKit/Source/core/loader/FrameLoaderTypes.h b/third_party/WebKit/Source/core/loader/FrameLoaderTypes.h
index 97a514633ff62dd8ebcc23a2041c7031821d797b..b4621f49c745db88fa082534f75bf7de665465d8 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoaderTypes.h
+++ b/third_party/WebKit/Source/core/loader/FrameLoaderTypes.h
@@ -32,14 +32,18 @@
 namespace blink {
 
 // See WebFrameLoadType in public/web/WebFrameLoadType.h for details.
+// These values are used for UMA histogram. New enum values can be added, but
+// existing enums must never be renumbered or deleted and reused.
 enum FrameLoadType {
-  kFrameLoadTypeStandard,
-  kFrameLoadTypeBackForward,
-  kFrameLoadTypeReload,
-  kFrameLoadTypeReplaceCurrentItem,
-  kFrameLoadTypeInitialInChildFrame,
-  kFrameLoadTypeInitialHistoryLoad,
-  kFrameLoadTypeReloadBypassingCache,
+  kFrameLoadTypeStandard = 0,
+  kFrameLoadTypeBackForward = 1,
+  kFrameLoadTypeReload = 2,
+  kFrameLoadTypeReplaceCurrentItem = 3,
+  kFrameLoadTypeInitialInChildFrame = 4,
+  kFrameLoadTypeInitialHistoryLoad = 5,
+  kFrameLoadTypeReloadBypassingCache = 6,
+  // kFrameLoadTypeCount is just a placeholder to indicate the count of types.
+  kFrameLoadTypeCount

[tdresser, 2017/06/12 20:54:19]

I think 
kFrameLoadTypeLast = kFrameLoadTypeReloadBypassingCache 
might clean this up a bit - I think you'd no longer need to include it in
switches.

[Liquan (Max) Gu, 2017/06/12 21:51:31]

Yes it does. Thanks!

 };
 
 enum NavigationType {