Adding Chrome-side WebVR interface

mojo/common/weak_binding_set.h

 // Copyright 2014 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.
 
 #ifndef MOJO_COMMON_WEAK_BINDING_SET_H_
 #define MOJO_COMMON_WEAK_BINDING_SET_H_
 
 #include <algorithm>
 #include <vector>
 
@@ skipping 24 matching lines @@
   }
 
   void CloseAllBindings() {
     for (const auto& it : bindings_) {
       if (it)
         it->Close();
     }
     bindings_.clear();
   }
 
+  bool empty() const { return bindings_.empty(); }
+
  private:
   // ErrorHandler implementation.
   void OnConnectionError() override {
     // Clear any deleted bindings.
     bindings_.erase(
         std::remove_if(bindings_.begin(), bindings_.end(),
                        [](const base::WeakPtr<WeakBinding<Interface>>& p) {
           return p.get() == nullptr;
         }),
         bindings_.end());
@@ skipping 42 matching lines @@
   mojo::Binding<Interface> binding_;
   ErrorHandler* error_handler_;
   base::WeakPtrFactory<WeakBinding> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WeakBinding);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_WEAK_BINDING_SET_H_