[Extensions Binding] Allow for registering custom hooks

extensions/renderer/api_binding.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_H_
 #define EXTENSIONS_RENDERER_API_BINDING_H_
 
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/supports_user_data.h"
 #include "extensions/renderer/argument_spec.h"
 #include "v8/include/v8.h"
 
 namespace base {
 class ListValue;
 }
 
 namespace gin {
 class Arguments;
 }
 
 namespace extensions {
+class APIBindingHooks;
 class APIEventHandler;
 
 // A class that vends v8::Objects for extension APIs. These APIs have function
 // interceptors for all exposed methods, which call back into the APIBinding.
 // The APIBinding then matches the calling arguments against an expected method
 // signature, throwing an error if they don't match.
 // There should only need to be a single APIBinding object for each API, and
 // each can vend multiple v8::Objects for different contexts.
 // TODO(devlin): What's the lifetime of this object?
 class APIBinding {
@@ skipping 17 matching lines @@
   using HandlerCallback = base::Callback<void(gin::Arguments*)>;
 
   // The ArgumentSpec::RefMap is required to outlive this object.
   // |type_definitions| and |event_definitions| may be null if the API does not
   // specify any types or events.
   APIBinding(const std::string& name,
              const base::ListValue& function_definitions,
              const base::ListValue* type_definitions,
              const base::ListValue* event_definitions,
              const APIMethodCallback& callback,
+             std::unique_ptr<APIBindingHooks> binding_hooks,
              ArgumentSpec::RefMap* type_refs);
   ~APIBinding();
 
   // Returns a new v8::Object for the API this APIBinding represents.
   v8::Local<v8::Object> CreateInstance(
       v8::Local<v8::Context> context,
       v8::Isolate* isolate,
       APIEventHandler* event_handler,
       const AvailabilityCallback& is_available);
 
@@ skipping 11 matching lines @@
 
   // A map from method name to expected signature.
   std::map<std::string, std::unique_ptr<APISignature>> signatures_;
 
   // The names of all events associated with this API.
   std::vector<std::string> event_names_;
 
   // The callback to use when an API is invoked with valid arguments.
   APIMethodCallback method_callback_;
 
+  // The registered hooks for this API. Null if there are no registered custom
+  // hooks.
+  std::unique_ptr<APIBindingHooks> binding_hooks_;
+
   // The reference map for all known types; required to outlive this object.
   const ArgumentSpec::RefMap* type_refs_;
 
   base::WeakPtrFactory<APIBinding> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(APIBinding);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_API_BINDING_H_