PlzNavigate: Enforce 'frame-src' CSP on the browser.

content/browser/frame_host/navigation_request.cc

Index: content/browser/frame_host/navigation_request.cc
diff --git a/content/browser/frame_host/navigation_request.cc b/content/browser/frame_host/navigation_request.cc
index 4a0c7cec73ffc4825e29fd96547d6e33faaef1c2..fb1e29a116addf85766b9a6b33ba3d48bcc03269 100644
--- a/content/browser/frame_host/navigation_request.cc
+++ b/content/browser/frame_host/navigation_request.cc
@@ -693,6 +693,13 @@ void NavigationRequest::OnRedirectChecksComplete(
     return;
   }
 
+  if (result == NavigationThrottle::BLOCK_REQUEST) {
+    OnRequestFailed(false, net::ERR_BLOCKED_BY_CLIENT);
+    // DO NOT ADD CODE after this. The previous call to OnRequestFailed has
+    // destroyed the NavigationRequest.
+    return;
+  }
+
   loader_->FollowRedirect();
 }