Make SyncMessageFilter work with WebKit threads.

SyncMessageFilter doesn't work with WebKit threads, because WebKit
threads don't have MessageLoops, so two threads send a message at the
same time, the first thread will stay blocked forever.

Also, it's unclear why we need to use MessageLoops as keys in a
hash_maps. The code doesn't use them at all.

TEST=a DB example that used to deadlock is working now
BUG=45253

Review URL: http://codereview.chromium.org/2360003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@48556 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 2 insertions, 15 deletions

diff --git a/ipc/ipc_sync_message_filter.h b/ipc/ipc_sync_message_filter.h
index 71d24c1..87fd612 100644
--- a/ipc/ipc_sync_message_filter.h
+++ b/ipc/ipc_sync_message_filter.h
@@ -6,28 +6,15 @@
 #define IPC_IPC_SYNC_MESSAGE_FILTER_H_
 
 #include "base/basictypes.h"
-#include "base/hash_tables.h"
 #include "base/lock.h"
 #include "base/ref_counted.h"
 #include "base/waitable_event.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_sync_message.h"
+#include <set>
 
 class MessageLoop;
 
-#if defined(COMPILER_GCC)
-// Allows us to use MessageLoop in a hash_map with gcc (MSVC is okay without
-// specifying this).
-namespace __gnu_cxx {
-template<>
-struct hash<MessageLoop*> {
-  size_t operator()(MessageLoop* message_loop) const {
-    return reinterpret_cast<size_t>(message_loop);
-  }
-};
-}
-#endif
-
 namespace IPC {
 
 class MessageReplyDeserializer;
@@ -63,7 +50,7 @@ class SyncMessageFilter : public ChannelProxy::MessageFilter,
   MessageLoop* listener_loop_;  // The process's main thread.
   MessageLoop* io_loop_;  // The message loop where the Channel lives.
 
-  typedef base::hash_map<MessageLoop*, PendingSyncMsg*> PendingSyncMessages;
+  typedef std::set<PendingSyncMsg*> PendingSyncMessages;
   PendingSyncMessages pending_sync_messages_;
 
   // Locks data members above.