ipc: Make sure that ChannelReader is destroyed correctly.

ipc/ipc_channel_reader.cc

Index: ipc/ipc_channel_reader.cc
diff --git a/ipc/ipc_channel_reader.cc b/ipc/ipc_channel_reader.cc
index a76b7e654b30a7a575e8350774a27288da43b931..f80d75d8e1ee98ca9c58c63ed1bd2e4bd7e9c094 100644
--- a/ipc/ipc_channel_reader.cc
+++ b/ipc/ipc_channel_reader.cc
@@ -20,8 +20,7 @@ ChannelReader::ChannelReader(Listener* listener) : listener_(listener) {
 }
 
 ChannelReader::~ChannelReader() {
-  if (!blocked_ids_.empty())
-    StopObservingAttachmentBroker();
+  DCHECK(blocked_ids_.empty());
 }
 
 ChannelReader::DispatchState ChannelReader::ProcessIncomingMessages() {
@@ -62,6 +61,13 @@ bool ChannelReader::IsHelloMessage(const Message& m) {
       m.type() == Channel::HELLO_MESSAGE_TYPE;
 }
 
+void ChannelReader::CleanUp() {
+  if (!blocked_ids_.empty()) {
+    StopObservingAttachmentBroker();
+    blocked_ids_.clear();
+  }
+}
+
 bool ChannelReader::TranslateInputData(const char* input_data,
                                        int input_data_len) {
   const char* p;