Revert "Bounce Blob URL revoking through the UI thread to give navigation a chance."

This reverts part of commit 8a556164.
The original change that caused the problems this was working around was
reverted, so also revert the workaround to fix the issues the workaround
caused.

Bug: 813224
Change-Id: Ic0659a38b6ddcf828c2476d6b9fa4e266c364b57
Reviewed-on: https://chromium-review.googlesource.com/998436Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548527}

content/browser/blob_storage/blob_dispatcher_host.cc

@@ -90,25 +90,6 @@ void BlobDispatcherHost::OnRegisterPublicBlobURL(const GURL& public_url,
   public_blob_urls_.insert(public_url);
 }
 
-namespace {
-
-void RevokePublicBlobURLHelperIO(
-    scoped_refptr<ChromeBlobStorageContext> context,
-    const GURL& public_url) {
-  context->context()->RevokePublicBlobURL(public_url);
-}
-
-void RevokePublicBlobURLHelperUI(
-    scoped_refptr<ChromeBlobStorageContext> context,
-    const GURL& public_url) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
-                          base::BindOnce(&RevokePublicBlobURLHelperIO,
-                                         std::move(context), public_url));
-}
-
-}  // namespace
-
 void BlobDispatcherHost::OnRevokePublicBlobURL(const GURL& public_url) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (!public_url.is_valid()) {
@@ -123,10 +104,8 @@ void BlobDispatcherHost::OnRevokePublicBlobURL(const GURL& public_url) {
                               BDH_TRACING_ENUM_LAST);
     return;
   }
+  context()->RevokePublicBlobURL(public_url);
   public_blob_urls_.erase(public_url);
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::BindOnce(&RevokePublicBlobURLHelperUI,
-                                         blob_storage_context_, public_url));
 }
 
 storage::BlobStorageContext* BlobDispatcherHost::context() {