[Blob URLs] Remove NOTREACHED from ProceedWithResponse.

NavigationRequest calls ProceedWithResponse if network service
isn't enabled because MojoAsyncResourceHandler depends on this.
Since we want to start using BlobURLLoader before network service
ships, this means BlobURLLoader.ProceedWithResponse can also be
called and thus shouldn't be a NOTREACHED. Replace with an empty
implementation instead since it isn't pausing the response anyway.

Bug: 800901
Change-Id: I7edc6a1b20f5aac2fa312a3a2770424464cf12df
Reviewed-on: https://chromium-review.googlesource.com/1103061
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568090}

storage/browser/blob/blob_url_loader.cc

@@ -98,9 +98,6 @@ void BlobURLLoader::FollowRedirect(
     const base::Optional<net::HttpRequestHeaders>& modified_request_headers) {
   NOTREACHED();
 }
-void BlobURLLoader::ProceedWithResponse() {
-  NOTREACHED();
-}
 
 mojo::ScopedDataPipeProducerHandle BlobURLLoader::PassDataPipe() {
   mojo::DataPipe data_pipe(kDefaultAllocationSize);

storage/browser/blob/blob_url_loader.h

@@ -43,7 +43,7 @@ class STORAGE_EXPORT BlobURLLoader : public storage::MojoBlobReader::Delegate,
                           to_be_removed_request_headers,
                       const base::Optional<net::HttpRequestHeaders>&
                           modified_request_headers) override;
-  void ProceedWithResponse() override;
+  void ProceedWithResponse() override {}
   void SetPriority(net::RequestPriority priority,
                    int32_t intra_priority_value) override {}
   void PauseReadingBodyFromNet() override {}