Ship `Document.onsecuritypolicyviolation`

We should have shipped this along with the violation events. It was
an oversight to leave the flag in the IDL file. Oops!

We shipped the event before we had Intents to Anything:
https://groups.google.com/a/chromium.org/d/msg/blink-dev/VYhixsNgEHM/SilKZTYOAwAJ
is the closest thing I can find, which exposed the event in Workers
~2.5 years ago.

Bug: 956690
Change-Id: I83adf4898f34ef1b7016ece7f032ab741c11dd09
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1588381Reviewed-by: Andy Paicu <andypaicu@chromium.org>
Commit-Queue: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656371}

third_party/blink/renderer/core/dom/document.idl

@@ -204,7 +204,7 @@ typedef (HTMLScriptElement or SVGScriptElement) HTMLOrSVGScriptElement;
     attribute EventHandler onfreeze;
     attribute EventHandler onresume;
     attribute EventHandler onsearch;
-    [RuntimeEnabled=ExperimentalContentSecurityPolicyFeatures] attribute EventHandler onsecuritypolicyviolation;
+    attribute EventHandler onsecuritypolicyviolation;
     attribute EventHandler onvisibilitychange;
 };
 

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -1335,6 +1335,7 @@ interface Document : Node
     getter onresume
     getter onscroll
     getter onsearch
+    getter onsecuritypolicyviolation
     getter onseeked
     getter onseeking
     getter onselect
@@ -1516,6 +1517,7 @@ interface Document : Node
     setter onresume
     setter onscroll
     setter onsearch
+    setter onsecuritypolicyviolation
     setter onseeked
     setter onseeking
     setter onselect