Auto merge of #11536 - izgzhen:add-blob-loader, r=Manishearth

Add blob loader

Add a blob loader to implement [Blob URL](https://w3c.github.io/FileAPI/#url). The related interfaces to script thread are also declared.

Progressing in parallel with PR #11534. Related to #11131.

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- [x] These changes fix part of #10539

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components/net_traits/lib.rs

@@ -43,6 +43,7 @@ use storage_thread::StorageThreadMsg;
 use url::Url;
 use websocket::header;
 
+pub mod blob_url_store;
 pub mod bluetooth_scanfilter;
 pub mod bluetooth_thread;
 pub mod filemanager_thread;