Clean up redirect handling logic in DocumentThreadableLoader

Removing the variable allow_redirect and calling
DispatchDidFailAccessControlCheck() immediately on each of check
points would be more readable.

Bug: 427429
Change-Id: Ib8d98c274104e2d5d6c65af123502b872a6658d7
Reviewed-on: https://chromium-review.googlesource.com/544646
Commit-Queue: Takeshi Yoshino <tyoshino@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490744}

third_party/WebKit/Source/core/loader/DocumentThreadableLoader.cpp

@@ -624,29 +624,30 @@ bool DocumentThreadableLoader::RedirectReceived(
         redirect_response, resource);
   }
 
-  String access_control_error_description;
-
   CrossOriginAccessControl::RedirectStatus redirect_status =
       CrossOriginAccessControl::CheckRedirectLocation(new_url);
-  bool allow_redirect =
-      redirect_status == CrossOriginAccessControl::kRedirectSuccess;
-  if (!allow_redirect) {
+  if (redirect_status != CrossOriginAccessControl::kRedirectSuccess) {
     StringBuilder builder;
     builder.Append("Redirect from '");
     builder.Append(original_url.GetString());
     builder.Append("' has been blocked by CORS policy: ");
     CrossOriginAccessControl::RedirectErrorString(builder, redirect_status,
                                                   new_url);
-    access_control_error_description = builder.ToString();
-  } else if (cors_flag_) {
+    DispatchDidFailAccessControlCheck(
+        ResourceError::CancelledDueToAccessCheckError(
+            original_url, ResourceRequestBlockedReason::kOther,
+            builder.ToString()));
+    return false;
+  }
+
+  if (cors_flag_) {
     // The redirect response must pass the access control check if the CORS
     // flag is set.
     CrossOriginAccessControl::AccessStatus cors_status =
         CrossOriginAccessControl::CheckAccess(
             redirect_response, new_request.GetFetchCredentialsMode(),
             GetSecurityOrigin());
-    allow_redirect = cors_status == CrossOriginAccessControl::kAccessAllowed;
-    if (!allow_redirect) {
+    if (cors_status != CrossOriginAccessControl::kAccessAllowed) {
       StringBuilder builder;
       builder.Append("Redirect from '");
       builder.Append(original_url.GetString());
@@ -656,18 +657,14 @@ bool DocumentThreadableLoader::RedirectReceived(
       CrossOriginAccessControl::AccessControlErrorString(
           builder, cors_status, redirect_response, GetSecurityOrigin(),
           request_context_);
-      access_control_error_description = builder.ToString();
+      DispatchDidFailAccessControlCheck(
+          ResourceError::CancelledDueToAccessCheckError(
+              original_url, ResourceRequestBlockedReason::kOther,
+              builder.ToString()));
+      return false;
     }
   }
 
-  if (!allow_redirect) {
-    DispatchDidFailAccessControlCheck(
-        ResourceError::CancelledDueToAccessCheckError(
-            original_url, ResourceRequestBlockedReason::kOther,
-            access_control_error_description));
-    return false;
-  }
-
   client_->DidReceiveRedirectTo(new_url);
 
   // FIXME: consider combining this with CORS redirect handling performed by