Change V8VarConverter::FromV8Value to complete synchronously if possible

content/renderer/pepper/resource_converter.h

 // Copyright 2013 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 CONTENT_RENDERER_PEPPER_RESOURCE_CONVERTER_H
 #define CONTENT_RENDERER_PEPPER_RESOURCE_CONVERTER_H
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 16 matching lines @@
 
 namespace content {
 
 class RendererPpapiHost;
 
 // This class is responsible for converting V8 vars to Pepper resources.
 class CONTENT_EXPORT ResourceConverter {
  public:
   virtual ~ResourceConverter();
 
-  // Flush() must be called before any vars created by the ResourceConverter
-  // are valid. It handles creating any resource hosts that need to be created.
+  // Reset the state of the resource converter.
+  virtual void Reset() = 0;
+
+  // Returns true if Flush() needs to be called before using any vars created
+  // by the resource converter.
+  virtual bool NeedsFlush() = 0;
+
+  // If NeedsFlush() is true then Flush() must be called before any vars created
+  // by the ResourceConverter are valid. It handles creating any resource hosts
+  // that need to be created. |callback| will always be called asynchronously.
   virtual void Flush(const base::Callback<void(bool)>& callback) = 0;
 
   // Attempts to convert a V8 object to a PP_Var with type PP_VARTYPE_RESOURCE.
   // On success, writes the resulting var to |result|, sets |was_resource| to
   // true and returns true. If |val| is not a resource, sets |was_resource| to
   // false and returns true. If an error occurs, returns false.
   virtual bool FromV8Value(v8::Handle<v8::Object> val,
                            v8::Handle<v8::Context> context,
                            PP_Var* result,
                            bool* was_resource) = 0;
 
   // Attempts to convert a PP_Var to a V8 object. |var| must have type
   // PP_VARTYPE_RESOURCE. On success, writes the resulting value to |result| and
   // returns true. If an error occurs, returns false.
   virtual bool ToV8Value(const PP_Var& var,
                          v8::Handle<v8::Context> context,
                          v8::Handle<v8::Value>* result) = 0;
 };
 
 class ResourceConverterImpl : public ResourceConverter {
  public:
   ResourceConverterImpl(PP_Instance instance, RendererPpapiHost* host);
   virtual ~ResourceConverterImpl();
 
   // ResourceConverter overrides.
+  virtual void Reset() OVERRIDE;
+  virtual bool NeedsFlush() OVERRIDE;
   virtual void Flush(const base::Callback<void(bool)>& callback) OVERRIDE;
   virtual bool FromV8Value(v8::Handle<v8::Object> val,
                            v8::Handle<v8::Context> context,
                            PP_Var* result,
                            bool* was_resource) OVERRIDE;
   virtual bool ToV8Value(const PP_Var& var,
                          v8::Handle<v8::Context> context,
                          v8::Handle<v8::Value>* result) OVERRIDE;
 
  private:
@@ skipping 21 matching lines @@
   // conveniently passed to |CreateBrowserResourceHosts|.
   std::vector<IPC::Message> browser_host_create_messages_;
   // A list of the resource vars associated with browser hosts.
   std::vector<scoped_refptr<HostResourceVar> > browser_vars_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceConverterImpl);
 };
 
 }  // namespace content
 #endif  // CONTENT_RENDERER_PEPPER_RESOURCE_CONVERTER_H