Cast: make global_instance_ more strict

chrome/renderer/media/cast_ipc_dispatcher.cc

Index: chrome/renderer/media/cast_ipc_dispatcher.cc
diff --git a/chrome/renderer/media/cast_ipc_dispatcher.cc b/chrome/renderer/media/cast_ipc_dispatcher.cc
index 3d71e922035e48bc9cab52832ae859d8377b1060..cb8c6ea17d9e2e01f6dba458e6290c1888a68d31 100644
--- a/chrome/renderer/media/cast_ipc_dispatcher.cc
+++ b/chrome/renderer/media/cast_ipc_dispatcher.cc
@@ -20,8 +20,7 @@ CastIPCDispatcher::CastIPCDispatcher(
 
 CastIPCDispatcher::~CastIPCDispatcher() {
   DCHECK(io_message_loop_->BelongsToCurrentThread());
-  // Unfortunately, you do not always get a OnFilterRemoved call.
-  global_instance_ = NULL;
+  DCHECK(!global_instance_);
 }
 
 CastIPCDispatcher* CastIPCDispatcher::Get() {
@@ -74,6 +73,7 @@ void CastIPCDispatcher::OnFilterRemoved() {
 void CastIPCDispatcher::OnChannelClosing() {
   DCHECK(io_message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(this, global_instance_);
+  global_instance_ = NULL;

[acolwell GONE FROM CHROMIUM, 2014/02/19 00:11:24]

Doesn't the DCHECK in OnFilterRemoved() fire if you add this since the
ChannelProxy::Context::OnChannelClosed() calls that method immediately after
this method.
(https://code.google.com/p/chromium/codesearch#chromium/src/ipc/ipc_channel_pr...)

[hubbe, 2014/02/19 00:29:51]

You're right. Fixed.

   channel_ = NULL;
 }