Mojo C++ bindings: refactor SyncHandleWatcher.

mojo/public/cpp/bindings/lib/connector.h

Index: mojo/public/cpp/bindings/lib/connector.h
diff --git a/mojo/public/cpp/bindings/lib/connector.h b/mojo/public/cpp/bindings/lib/connector.h
index e00936c111644ee98674f741ebe58e58e09b5181..13235b2ee253dfe1b3acc05c218d15d677713d1c 100644
--- a/mojo/public/cpp/bindings/lib/connector.h
+++ b/mojo/public/cpp/bindings/lib/connector.h
@@ -10,6 +10,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "mojo/public/cpp/bindings/callback.h"
+#include "mojo/public/cpp/bindings/lib/sync_handle_watcher.h"
 #include "mojo/public/cpp/bindings/message.h"
 #include "mojo/public/cpp/system/core.h"
 #include "mojo/public/cpp/system/watcher.h"
@@ -119,20 +120,18 @@ class Connector : public MessageReceiver {
     return message_pipe_.get();
   }
 
-  // Requests to register |message_pipe_| with SyncHandleWatcher whenever this
-  // instance is expecting incoming messages.
-  //
-  // Please note that UnregisterSyncHandleWatch() needs to be called as many
-  // times as successful RegisterSyncHandleWatch() calls in order to cancel the
-  // effect.
-  bool RegisterSyncHandleWatch();
-  void UnregisterSyncHandleWatch();
-
-  // Watches all handles registered with SyncHandleWatcher on the same thread.
-  // The method returns true when |*should_stop| is set to true; returns false
-  // when any failure occurs during the watch, including |message_pipe_| is
-  // closed.
-  bool RunSyncHandleWatch(const bool* should_stop);
+  // Allows |message_pipe_| be watched while others perform sync handle watching
+  // on the same thread. Please see comments of
+  // SyncHandleWatcher::AllowWokenUpBySyncWatchOnSameThread().
+  void AllowWokenUpBySyncWatchOnSameThread();
+
+  // Watches |message_pipe_| (as well as other handles registered to be watched
+  // together) synchronously.
+  // This method:
+  //   - returns true when |should_stop| is set to true;
+  //   - return false when any error occurs, including |message_pipe_| being
+  //     closed.
+  bool SyncWatch(const bool* should_stop);
 
   // Whether currently the control flow is inside the sync handle watcher
   // callback.
@@ -164,6 +163,8 @@ class Connector : public MessageReceiver {
   // Cancels any calls made to |waiter_|.
   void CancelWait();
 
+  void EnsureSyncWatcherExists();
+
   Closure connection_error_handler_;
 
   ScopedMessagePipeHandle message_pipe_;
@@ -181,14 +182,11 @@ class Connector : public MessageReceiver {
   // protect modifications to |message_pipe_| and |drop_writes_|.
   scoped_ptr<base::Lock> lock_;
 
-  // If non-zero, |message_pipe_| should be registered with SyncHandleWatcher.
-  size_t register_sync_handle_watch_count_;
-  // Whether |message_pipe_| has been registered with SyncHandleWatcher.
-  bool registered_with_sync_handle_watcher_;
+  scoped_ptr<SyncHandleWatcher> sync_watcher_;
+  bool allow_woken_up_by_others_;
   // If non-zero, currently the control flow is inside the sync handle watcher
   // callback.
   size_t sync_handle_watcher_callback_count_;
-  scoped_refptr<base::RefCountedData<bool>> should_stop_sync_handle_watch_;
 
   base::ThreadChecker thread_checker_;