Use ConnectionErrorObserver, not callbacks, for error handling.

blimp/net/blimp_message_output_buffer_unittest.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 "blimp/net/blimp_message_output_buffer.h"
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 167 matching lines @@
   net::TestCompletionCallback complete_cb_2;
 
   AddOutputExpectation(input_msg_);
   AddOutputExpectation(input_msg_);
 
   // Accumulate two messages.
   buffer_->ProcessMessage(base::WrapUnique(new BlimpMessage(input_msg_)),
                           complete_cb_1.callback());
   ASSERT_EQ(1, buffer_->GetBufferByteSizeForTest());
 
-  // First write attempt, which fails.
+  // First write attempt, which fails. The output buffer isn't notified of the
+  // connection loss, because the write callback is silently dropped.
   ASSERT_TRUE(captured_cb_.is_null());
   buffer_->SetOutputProcessor(&output_processor_);
   ASSERT_FALSE(captured_cb_.is_null());
-  base::ResetAndReturn(&captured_cb_).Run(net::ERR_FAILED);
   ASSERT_EQ(1, buffer_->GetBufferByteSizeForTest());
   ASSERT_EQ(0, buffer_->GetUnacknowledgedMessageCountForTest());
 
   // Simulate disconnect.
   buffer_->SetOutputProcessor(nullptr);
 
   // Reconnect. Should immediately try to write the contents of the buffer.
   buffer_->SetOutputProcessor(&output_processor_);
   ASSERT_FALSE(captured_cb_.is_null());
   base::ResetAndReturn(&captured_cb_).Run(net::OK);
@@ skipping 51 matching lines @@
 
   // Remote end acknowledges #1, buffer should be empty.
   buffer_->OnMessageCheckpoint(2);
   ASSERT_EQ(0, buffer_->GetBufferByteSizeForTest());
   ASSERT_EQ(0, buffer_->GetUnacknowledgedMessageCountForTest());
   EXPECT_EQ(net::OK, complete_cb_2.WaitForResult());
 }
 
 }  // namespace
 }  // namespace blimp