Add usage counters to XSSAuditor.

third_party/WebKit/Source/core/frame/UseCounter.h

Index: third_party/WebKit/Source/core/frame/UseCounter.h
diff --git a/third_party/WebKit/Source/core/frame/UseCounter.h b/third_party/WebKit/Source/core/frame/UseCounter.h
index 3c30e892782750686e143a269808570357aa67b9..fb02c4cd8f1cbcb269561e98f12db1a45687c2cb 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.h
+++ b/third_party/WebKit/Source/core/frame/UseCounter.h
@@ -1296,6 +1296,12 @@ public:
         PresentationConnectionListConnectionAvailableEventListener = 1555,
         WebAudioAutoplayCrossOriginIframe = 1556,
         ScriptInvalidTypeOrLanguage = 1557,
+        XSSAuditorBlockedScript = 1558,
+        XSSAuditorBlockedScriptAndEntirePage = 1559,

[Tom Sepez, 2016/09/15 16:39:08]

nit: maybe just call this XSSAuditorBlockedEntirePage and save some characters.

+        XSSAuditorDisabled = 1560,
+        XSSAuditorEnabledFilter = 1561,
+        XSSAuditorEnabledBlock = 1562,
+
         // Add new features immediately above this line. Don't change assigned
         // numbers of any item, and don't reuse removed slots.
         // Also, run update_use_counter_feature_enum.py in chromium/src/tools/metrics/histograms/