Teach the GCM Driver how to decrypt incoming messages.

components/gcm_driver/gcm_driver.cc

 // Copyright 2014 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/gcm_driver.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "components/gcm_driver/gcm_app_handler.h"
 
 namespace gcm {
 
+namespace {
+
+// TODO(peter): Implement an event for GCMAppHandlers that should be called
+// when decryption of an incoming message has failed.
+void DecryptionFailedCallback(

[Michael van Ouwerkerk, 2015/10/02 14:30:42]

nit: Can we add some Info level logging for when this happens? Or some UMA?

[Peter Beverloo, 2015/10/02 15:01:22]

Each path towards reaching this message will already output a DLOG(ERROR), so
this should be obvious. We'll need an |onpusherror| event prior to shipping as
well, which will be covered by UMA.

+    GCMEncryptionProvider::DecryptionFailure reason) {}
+
 const size_t kMaxSenders = 100;
 
+}  // namespace
+
 InstanceIDHandler::InstanceIDHandler() {
 }
 
 InstanceIDHandler::~InstanceIDHandler() {
 }
 
 void InstanceIDHandler::DeleteAllTokensForApp(
     const std::string& app_id, const DeleteTokenCallback& callback) {
   DeleteToken(app_id, "*", "*", callback);
 }
@@ skipping 223 matching lines @@
 bool GCMDriver::HasRegisterCallback(const std::string& app_id) {
   return register_callbacks_.find(app_id) != register_callbacks_.end();
 }
 
 void GCMDriver::ClearCallbacks() {
   register_callbacks_.clear();
   unregister_callbacks_.clear();
   send_callbacks_.clear();
 }
 
+void GCMDriver::DispatchMessage(const std::string& app_id,
+                                const IncomingMessage& message) {
+  if (!encryption_provider_.IsEncryptedMessage(message)) {
+    GetAppHandler(app_id)->OnMessage(app_id, message);
+    return;
+  }
+
+  encryption_provider_.DecryptMessage(
+      app_id, message,
+      base::Bind(&GCMDriver::DispatchMessage,
+                 weak_ptr_factory_.GetWeakPtr(), app_id),
+      base::Bind(&DecryptionFailedCallback));
+}
+
 void GCMDriver::RegisterAfterUnregister(
     const std::string& app_id,
     const std::vector<std::string>& normalized_sender_ids,
     const UnregisterCallback& unregister_callback,
     GCMClient::Result result) {
   // Invoke the original unregister callback.
   unregister_callback.Run(result);
 
   // Trigger the pending registration.
   DCHECK(register_callbacks_.find(app_id) != register_callbacks_.end());
   RegisterImpl(app_id, normalized_sender_ids);
 }
 
 }  // namespace gcm