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

content/browser/frame_host/ancestor_throttle.cc

Index: content/browser/frame_host/ancestor_throttle.cc
diff --git a/content/browser/frame_host/ancestor_throttle.cc b/content/browser/frame_host/ancestor_throttle.cc
index cba286784a2e914a9f35e79578900da220198d10..ca87f0a221d797c54f9304669bd016aa961c9bcc 100644
--- a/content/browser/frame_host/ancestor_throttle.cc
+++ b/content/browser/frame_host/ancestor_throttle.cc
@@ -11,11 +11,9 @@
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/navigation_handle_impl.h"
-#include "content/browser/frame_host/navigation_request.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/navigation_throttle.h"
-#include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/console_message_level.h"
 #include "net/http/http_response_headers.h"
 #include "url/origin.h"
@@ -167,43 +165,6 @@
   return NavigationThrottle::BLOCK_RESPONSE;
 }
 
-NavigationThrottle::ThrottleCheckResult
-AncestorThrottle::CheckContentSecurityPolicyFrameSrc(bool is_redirect) {
-  // If PlzNavigate is enabled, "frame-src" is enforced on the browser side,
-  // else on the renderer side.
-  if (!IsBrowserSideNavigationEnabled())
-    return NavigationThrottle::PROCEED;
-
-  const GURL& url = navigation_handle()->GetURL();
-  if (url.SchemeIs(url::kAboutScheme))
-    return NavigationThrottle::PROCEED;
-
-  NavigationHandleImpl* handle =
-      static_cast<NavigationHandleImpl*>(navigation_handle());
-
-  if (handle->should_check_main_world_csp() == CSPDisposition::DO_NOT_CHECK)
-    return NavigationThrottle::PROCEED;
-
-  FrameTreeNode* parent_ftn = handle->frame_tree_node()->parent();
-  DCHECK(parent_ftn);
-  RenderFrameHostImpl* parent = parent_ftn->current_frame_host();
-  DCHECK(parent);
-
-  if (!parent->IsAllowedByCsp(CSPDirective::FrameSrc, url, is_redirect))
-    return NavigationThrottle::BLOCK_REQUEST;
-
-  return NavigationThrottle::PROCEED;
-}
-
-NavigationThrottle::ThrottleCheckResult AncestorThrottle::WillStartRequest() {
-  return CheckContentSecurityPolicyFrameSrc(false);
-}
-
-NavigationThrottle::ThrottleCheckResult
-AncestorThrottle::WillRedirectRequest() {
-  return CheckContentSecurityPolicyFrameSrc(true);
-}
-
 AncestorThrottle::AncestorThrottle(NavigationHandle* handle)
     : NavigationThrottle(handle) {}