Remove CORS scheme check temporarily

The scheme check added at
https://crrev.com/43b8facd3a2fbfb8f75b455f07d64acc2c13fb5c caused some
issues on WebView. This change deletes the check temporarily.

TBR=yhirano@chromium.org

(cherry picked from commit 14314b0)

Bug: 898589
Change-Id: I6126b3b25f8700fc0547fa2c70b62bd183cc5e23
Reviewed-on: https://chromium-review.googlesource.com/c/1298828
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Richard Coles <torne@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#602736}
Reviewed-on: https://chromium-review.googlesource.com/c/1299436
Reviewed-by: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/branch-heads/3578@{#320}
Cr-Branched-From: 4226ddf-refs/heads/master@{#599034}

third_party/blink/renderer/platform/loader/fetch/resource_fetcher.cc

@@ -753,13 +753,8 @@ base::Optional<ResourceRequestBlockedReason> ResourceFetcher::PrepareRequest(
     DCHECK(!options.cors_flag);
     params.MutableOptions().cors_flag = CORS::CalculateCORSFlag(
         params.Url(), origin.get(), resource_request.GetFetchRequestMode());
-    // Cross-origin requests are only allowed certain registered schemes.
-    if (options.cors_flag && !SchemeRegistry::ShouldTreatURLSchemeAsCORSEnabled(
-                                 params.Url().Protocol())) {
-      // This won't create a CORS related console error.
-      // TODO(yhirano): Fix this.
-      return ResourceRequestBlockedReason::kOther;
-    }
+    // TODO(yhirano): Reject requests for non CORS-enabled schemes.
+    // See https://crrev.com/c/1298828.
     resource_request.SetAllowStoredCredentials(CORS::CalculateCredentialsFlag(
         resource_request.GetFetchCredentialsMode(),
         CORS::CalculateResponseTainting(