Revert of Hook up the Push API with GCM's new ability to own encryption keys.

components/gcm_driver/crypto/gcm_key_store.cc

 // Copyright 2015 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 "components/gcm_driver/crypto/gcm_key_store.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "components/leveldb_proto/proto_database_impl.h"
 #include "crypto/curve25519.h"
 #include "crypto/random.h"
 
 namespace gcm {
 
 enum class GCMKeyStore::State {
    UNINITIALIZED,
    INITIALIZING,
    INITIALIZED,
    FAILED
 };
 
 GCMKeyStore::GCMKeyStore(
     const base::FilePath& key_store_path,
-    const scoped_refptr<base::SequencedTaskRunner>& blocking_task_runner)
+    scoped_refptr<base::SequencedTaskRunner> background_task_runner)
     : key_store_path_(key_store_path),
-      blocking_task_runner_(blocking_task_runner),
+      database_(new leveldb_proto::ProtoDatabaseImpl<EncryptionData>(
+                    background_task_runner)),
       state_(State::UNINITIALIZED) {
-  DCHECK(blocking_task_runner);
 }
 
 GCMKeyStore::~GCMKeyStore() {}
 
 void GCMKeyStore::GetKeys(const std::string& app_id,
                           const KeysCallback& callback) {
   LazyInitialize(base::Bind(&GCMKeyStore::GetKeysAfterInitialize, this, app_id,
                             callback));
 }
 
@@ skipping 121 matching lines @@
     done_closure.Run();
     return;
   }
 
   delayed_task_controller_.AddTask(done_closure);
   if (state_ == State::INITIALIZING)
     return;
 
   state_ = State::INITIALIZING;
 
-  database_.reset(new leveldb_proto::ProtoDatabaseImpl<EncryptionData>(
-      blocking_task_runner_));
-
   database_->Init(key_store_path_,
                   base::Bind(&GCMKeyStore::DidInitialize, this));
 }
 
 void GCMKeyStore::DidInitialize(bool success) {
   if (!success) {
     DVLOG(1) << "Unable to initialize the GCM Key Store.";
     state_ = State::FAILED;
 
     delayed_task_controller_.SetReady();
@@ skipping 17 matching lines @@
     DCHECK_EQ(1, entry.keys_size());
     key_pairs_[entry.app_id()] = entry.keys(0);
   }
 
   state_ = State::INITIALIZED;
 
   delayed_task_controller_.SetReady();
 }
 
 }  // namespace gcm