[Extensions Bindings] Add a bridge to use current custom bindings

extensions/renderer/api_binding_test.h

 // Copyright 2016 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 EXTENSIONS_RENDERER_API_BINDING_TEST_H_
 #define EXTENSIONS_RENDERER_API_BINDING_TEST_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "v8/include/v8.h"
 
 namespace gin {
 class ContextHolder;
 class IsolateHolder;
 }
 
 namespace extensions {
 
 // A common unit test class for testing API bindings. Creates an isolate and an
 // initial v8 context, and checks for v8 leaks at the end of the test.
 class APIBindingTest : public testing::Test {
  protected:
   APIBindingTest();
   ~APIBindingTest() override;
 
+  // Returns the V8 ExtensionConfiguration to use for contexts. The default
+  // implementation returns null.
+  virtual v8::ExtensionConfiguration* GetV8ExtensionConfiguration();
+
   // testing::Test:
   void SetUp() override;
   void TearDown() override;
 
   v8::Local<v8::Context> ContextLocal();
   void DisposeContext();
 
   // Returns the associated isolate. Defined out-of-line to avoid the include
   // for IsolateHolder in the header.
   v8::Isolate* isolate();
 
  private:
   base::MessageLoop message_loop_;
   std::unique_ptr<gin::IsolateHolder> isolate_holder_;
   std::unique_ptr<gin::ContextHolder> context_holder_;
 
   DISALLOW_COPY_AND_ASSIGN(APIBindingTest);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_API_BINDING_TEST_H_