Revert 219383 "UMA data collector for cross-site documents(XSD)"

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
===================================================================
--- content/public/common/content_switches.cc	(revision 219467)
+++ content/public/common/content_switches.cc	(working copy)
@@ -41,12 +41,6 @@
 // Blacklist the GPU for WebGL.
 const char kBlacklistWebGL[]                = "blacklist-webgl";
 
-// Block cross-site documents (i.e., HTML/XML/JSON) from being loaded in
-// subresources when a document is not supposed to read them.  This will later
-// allow us to block them from the entire renderer process when site isolation
-// is enabled.
-const char kBlockCrossSiteDocuments[]     = "block-cross-site-documents";
-
 // Causes the browser process to throw an assertion on startup.
 const char kBrowserAssertTest[]             = "assert-test";