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

components/gcm_driver/crypto/gcm_encryption_handler.h

Index: components/gcm_driver/crypto/gcm_encryption_handler.h
diff --git a/components/gcm_driver/crypto/gcm_encryption_handler.h b/components/gcm_driver/crypto/gcm_encryption_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..a1a9dcb784c7d9ce2956d2bb95477435a36107c4
--- /dev/null
+++ b/components/gcm_driver/crypto/gcm_encryption_handler.h
@@ -0,0 +1,61 @@
+// 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.
+
+#ifndef COMPONENTS_GCM_DRIVER_CRYPTO_GCM_ENCRYPTION_HANDLER_H_
+#define COMPONENTS_GCM_DRIVER_CRYPTO_GCM_ENCRYPTION_HANDLER_H_
+
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+
+namespace base {
+class FilePath;
+class SequencedTaskRunner;
+}
+
+namespace gcm {
+
+class GCMKeyStore;
+class KeyPair;
+
+// Interface through which the GCM Driver deals with encryption. Responsible for

[jianli, 2015/07/17 20:55:21]

"Interface" sounds a bit misleading. How about "bridge"?

[Peter Beverloo, 2015/07/20 17:55:53]

I called it a provider per your next comment.

+// both key management and decryption of incoming messages.
+class GCMEncryptionHandler {

[jianli, 2015/07/17 20:55:21]

Handler suffix sounds not good enough to indicate what this class is intended
for. How about GCMEncryptionChannel, or GCMEncryptionProvider?

[Peter Beverloo, 2015/07/20 17:55:53]

Done. (GCMEncryptionProvider)

+ public:
+  // Callback to be invoked when the public encryption key is available.
+  using KeyCallback = base::Callback<void(const std::vector<uint8_t>&)>;
+
+  GCMEncryptionHandler(
+      const base::FilePath& store_path,
+      scoped_refptr<base::SequencedTaskRunner> blocking_task_runner);

[jianli, 2015/07/17 20:55:21]

const scoped_refptr<>&

[Peter Beverloo, 2015/07/20 17:55:53]

Done.

+  ~GCMEncryptionHandler();
+
+  // Retrieves the public encryption key belonging to |app_id|. If no keys have
+  // been associated with |app_id| yet, they will be created.
+  void GetPublicEncryptionKey(const std::string& app_id,

[jianli, 2015/07/17 20:55:21]

I think the shorter name GetPublicKey is simpler and easier to understand.

[Peter Beverloo, 2015/07/20 17:55:53]

Done.

+                              const KeyCallback& callback);
+
+ private:
+  void DidGetPublicEncryptionKey(const std::string& app_id,
+                                 const KeyCallback& callback,
+                                 const KeyPair& pair);
+
+  void DidCreatePublicEncryptionKey(const KeyCallback& callback,
+                                    const KeyPair& pair);
+
+  scoped_refptr<GCMKeyStore> key_store_;
+
+  base::WeakPtrFactory<GCMEncryptionHandler> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(GCMEncryptionHandler);
+};
+
+}  // namespace gcm
+
+#endif  // COMPONENTS_GCM_DRIVER_CRYPTO_GCM_ENCRYPTION_HANDLER_H_