Bug 1329288 - Bring back ContentPolicy check within nsDocShell. r=smaug

docshell/base/nsDocShell.cpp

@@ -69,6 +69,7 @@
 #include "nsIScriptSecurityManager.h"
 #include "nsIScriptObjectPrincipal.h"
 #include "nsIScrollableFrame.h"
+#include "nsContentPolicyUtils.h" // NS_CheckContentLoadPolicy(...)
 #include "nsISeekableStream.h"
 #include "nsAutoPtr.h"
 #include "nsQueryObject.h"
@@ -9882,6 +9883,23 @@ nsDocShell::InternalLoad(nsIURI* aURI,
 #endif
     }
 
+    int16_t shouldLoad = nsIContentPolicy::ACCEPT;
+    rv = NS_CheckContentLoadPolicy(contentType,
+                                   aURI,
+                                   aTriggeringPrincipal,
+                                   requestingContext,
+                                   EmptyCString(),  // mime guess
+                                   nullptr,  // extra
+                                   &shouldLoad);
+  
+    if (NS_FAILED(rv) || NS_CP_REJECTED(shouldLoad)) {
+      if (NS_SUCCEEDED(rv) && shouldLoad == nsIContentPolicy::REJECT_TYPE) {
+        return NS_ERROR_CONTENT_BLOCKED_SHOW_ALT;
+      }
+
+      return NS_ERROR_CONTENT_BLOCKED;
+    }
+
     // If HSTS priming was set by nsMixedContentBlocker::ShouldLoad, and we
     // would block due to mixed content, go ahead and block here. If we try to
     // proceed with priming, we will error out later on.