[BlobAsync] Faster shortcuttin, make renderer controller leaky & alive.

content/browser/blob_storage/blob_dispatcher_host.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/blob_storage/blob_dispatcher_host.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "content/browser/bad_message.h"
@@ skipping 170 matching lines @@
   const BlobStorageRegistry::Entry* entry = context->registry().GetEntry(uuid);
   if (!entry || entry->state == BlobStorageRegistry::BlobState::BROKEN) {
     // We ignore messages for blobs that don't exist to handle the case where
     // the renderer de-refs a blob that we're still constructing, and there are
     // no references to that blob. We ignore broken as well, in the case where
     // we decided to break a blob and the renderer also decided to cancel.
     // Note: if a blob is broken, then it can't be in the async_builder.
     // Second, if the last dereference of the blob happened on a different host,
     // then we still haven't gotten rid of the 'building' state in the original
     // host. So we call cancel just in case this happens.
-    async_builder_.CancelBuildingBlob(
-        uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING,
-        context);
+    if (async_builder_.IsBeingBuilt(uuid)) {
+      async_builder_.CancelBuildingBlob(
+          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING,
+          context);
+    }
     return;
   }
   if (!async_builder_.IsBeingBuilt(uuid)) {
     SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
     return;
   }
   VLOG(1) << "Blob construction of " << uuid << " cancelled by renderer. "
           << " Reason: " << static_cast<int>(code) << ".";
   async_builder_.CancelBuildingBlob(uuid, code, context);
 }
@@ skipping 120 matching lines @@
     context->RevokePublicBlobURL(url);
   }
   for (const auto& uuid_refnum_pair : blobs_inuse_map_) {
     for (int i = 0; i < uuid_refnum_pair.second; ++i)
       context->DecrementBlobRefCount(uuid_refnum_pair.first);
   }
   async_builder_.CancelAll(context);
 }
 
 }  // namespace content