Revert of Replace NPObject usage in ppapi with gin

content/renderer/pepper/message_channel.cc

 // Copyright (c) 2012 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.
 
 #include "content/renderer/pepper/message_channel.h"
 
 #include <cstdlib>
 #include <string>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "content/public/common/content_client.h"
 #include "content/public/renderer/content_renderer_client.h"
 #include "content/renderer/pepper/host_array_buffer_var.h"
+#include "content/renderer/pepper/npapi_glue.h"
 #include "content/renderer/pepper/pepper_plugin_instance_impl.h"
-#include "content/renderer/pepper/pepper_try_catch.h"
 #include "content/renderer/pepper/plugin_module.h"
-#include "content/renderer/pepper/plugin_object.h"
 #include "content/renderer/pepper/v8_var_converter.h"
-#include "gin/arguments.h"
-#include "gin/converter.h"
-#include "gin/function_template.h"
-#include "gin/object_template_builder.h"
-#include "gin/public/gin_embedders.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 #include "ppapi/shared_impl/scoped_pp_var.h"
 #include "ppapi/shared_impl/var.h"
 #include "ppapi/shared_impl/var_tracker.h"
 #include "third_party/WebKit/public/web/WebBindings.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebDOMMessageEvent.h"
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebNode.h"
@@ skipping 20 matching lines @@
 const char kPostMessageAndAwaitResponse[] = "postMessageAndAwaitResponse";
 const char kV8ToVarConversionError[] =
     "Failed to convert a PostMessage "
     "argument from a JavaScript value to a PP_Var. It may have cycles or be of "
     "an unsupported type.";
 const char kVarToV8ConversionError[] =
     "Failed to convert a PostMessage "
     "argument from a PP_Var to a Javascript value. It may have cycles or be of "
     "an unsupported type.";
 
-bool HasDevPermission() {
+// Helper function to get the MessageChannel that is associated with an
+// NPObject*.
+MessageChannel* ToMessageChannel(NPObject* object) {
+  return static_cast<MessageChannel::MessageChannelNPObject*>(object)
+      ->message_channel.get();
+}
+
+NPObject* ToPassThroughObject(NPObject* object) {
+  MessageChannel* channel = ToMessageChannel(object);
+  return channel ? channel->passthrough_object() : NULL;
+}
+
+// Return true iff |identifier| is equal to |string|.
+bool IdentifierIs(NPIdentifier identifier, const char string[]) {
+  return WebBindings::getStringIdentifier(string) == identifier;
+}
+
+bool HasDevChannelPermission(NPObject* channel_object) {
+  MessageChannel* channel = ToMessageChannel(channel_object);
+  if (!channel)
+    return false;
   return GetContentClient()->renderer()->IsPluginAllowedToUseDevChannelAPIs();
 }
 
+//------------------------------------------------------------------------------
+// Implementations of NPClass functions.  These are here to:
+// - Implement postMessage behavior.
+// - Forward calls to the 'passthrough' object to allow backwards-compatibility
+//   with GetInstanceObject() objects.
+//------------------------------------------------------------------------------
+NPObject* MessageChannelAllocate(NPP npp, NPClass* the_class) {
+  return new MessageChannel::MessageChannelNPObject;
+}
+
+void MessageChannelDeallocate(NPObject* object) {
+  MessageChannel::MessageChannelNPObject* instance =
+      static_cast<MessageChannel::MessageChannelNPObject*>(object);
+  delete instance;
+}
+
+bool MessageChannelHasMethod(NPObject* np_obj, NPIdentifier name) {
+  if (!np_obj)
+    return false;
+
+  if (IdentifierIs(name, kPostMessage))
+    return true;
+  if (IdentifierIs(name, kPostMessageAndAwaitResponse) &&
+      HasDevChannelPermission(np_obj)) {
+    return true;
+  }
+  // Other method names we will pass to the passthrough object, if we have one.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough)
+    return WebBindings::hasMethod(NULL, passthrough, name);
+  return false;
+}
+
+bool MessageChannelInvoke(NPObject* np_obj,
+                          NPIdentifier name,
+                          const NPVariant* args,
+                          uint32 arg_count,
+                          NPVariant* result) {
+  if (!np_obj)
+    return false;
+
+  MessageChannel* message_channel = ToMessageChannel(np_obj);
+  if (!message_channel)
+    return false;
+
+  // Check to see if we should handle this function ourselves.
+  if (IdentifierIs(name, kPostMessage) && (arg_count == 1)) {
+    message_channel->PostMessageToNative(&args[0]);
+    return true;
+  } else if (IdentifierIs(name, kPostMessageAndAwaitResponse) &&
+             (arg_count == 1) &&
+             HasDevChannelPermission(np_obj)) {
+    message_channel->PostBlockingMessageToNative(&args[0], result);
+    return true;
+  }
+
+  // Other method calls we will pass to the passthrough object, if we have one.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough) {
+    return WebBindings::invoke(
+        NULL, passthrough, name, args, arg_count, result);
+  }
+  return false;
+}
+
+bool MessageChannelInvokeDefault(NPObject* np_obj,
+                                 const NPVariant* args,
+                                 uint32 arg_count,
+                                 NPVariant* result) {
+  if (!np_obj)
+    return false;
+
+  // Invoke on the passthrough object, if we have one.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough) {
+    return WebBindings::invokeDefault(
+        NULL, passthrough, args, arg_count, result);
+  }
+  return false;
+}
+
+bool MessageChannelHasProperty(NPObject* np_obj, NPIdentifier name) {
+  if (!np_obj)
+    return false;
+
+  MessageChannel* message_channel = ToMessageChannel(np_obj);
+  if (message_channel) {
+    if (message_channel->GetReadOnlyProperty(name, NULL))
+      return true;
+  }
+
+  // Invoke on the passthrough object, if we have one.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough)
+    return WebBindings::hasProperty(NULL, passthrough, name);
+  return false;
+}
+
+bool MessageChannelGetProperty(NPObject* np_obj,
+                               NPIdentifier name,
+                               NPVariant* result) {
+  if (!np_obj)
+    return false;
+
+  // Don't allow getting the postMessage functions.
+  if (IdentifierIs(name, kPostMessage))
+    return false;
+  if (IdentifierIs(name, kPostMessageAndAwaitResponse) &&
+      HasDevChannelPermission(np_obj)) {
+     return false;
+  }
+  MessageChannel* message_channel = ToMessageChannel(np_obj);
+  if (message_channel) {
+    if (message_channel->GetReadOnlyProperty(name, result))
+      return true;
+  }
+
+  // Invoke on the passthrough object, if we have one.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough)
+    return WebBindings::getProperty(NULL, passthrough, name, result);
+  return false;
+}
+
+bool MessageChannelSetProperty(NPObject* np_obj,
+                               NPIdentifier name,
+                               const NPVariant* variant) {
+  if (!np_obj)
+    return false;
+
+  // Don't allow setting the postMessage functions.
+  if (IdentifierIs(name, kPostMessage))
+    return false;
+  if (IdentifierIs(name, kPostMessageAndAwaitResponse) &&
+      HasDevChannelPermission(np_obj)) {
+    return false;
+  }
+  // Invoke on the passthrough object, if we have one.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough)
+    return WebBindings::setProperty(NULL, passthrough, name, variant);
+  return false;
+}
+
+bool MessageChannelEnumerate(NPObject* np_obj,
+                             NPIdentifier** value,
+                             uint32_t* count) {
+  if (!np_obj)
+    return false;
+
+  // Invoke on the passthrough object, if we have one, to enumerate its
+  // properties.
+  NPObject* passthrough = ToPassThroughObject(np_obj);
+  if (passthrough) {
+    bool success = WebBindings::enumerate(NULL, passthrough, value, count);
+    if (success) {
+      // Add postMessage to the list and return it.
+      if (std::numeric_limits<size_t>::max() / sizeof(NPIdentifier) <=
+          static_cast<size_t>(*count) + 1)  // Else, "always false" x64 warning.
+        return false;
+      NPIdentifier* new_array = static_cast<NPIdentifier*>(
+          std::malloc(sizeof(NPIdentifier) * (*count + 1)));
+      std::memcpy(new_array, *value, sizeof(NPIdentifier) * (*count));
+      new_array[*count] = WebBindings::getStringIdentifier(kPostMessage);
+      std::free(*value);
+      *value = new_array;
+      ++(*count);
+      return true;
+    }
+  }
+
+  // Otherwise, build an array that includes only postMessage.
+  *value = static_cast<NPIdentifier*>(malloc(sizeof(NPIdentifier)));
+  (*value)[0] = WebBindings::getStringIdentifier(kPostMessage);
+  *count = 1;
+  return true;
+}
+
+NPClass message_channel_class = {
+    NP_CLASS_STRUCT_VERSION,      &MessageChannelAllocate,
+    &MessageChannelDeallocate,    NULL,
+    &MessageChannelHasMethod,     &MessageChannelInvoke,
+    &MessageChannelInvokeDefault, &MessageChannelHasProperty,
+    &MessageChannelGetProperty,   &MessageChannelSetProperty,
+    NULL,                         &MessageChannelEnumerate, };
+
 }  // namespace
 
 // MessageChannel --------------------------------------------------------------
 struct MessageChannel::VarConversionResult {
   VarConversionResult() : success_(false), conversion_completed_(false) {}
   void ConversionCompleted(const ScopedPPVar& var,
                            bool success) {
     conversion_completed_ = true;
     var_ = var;
     success_ = success;
   }
   const ScopedPPVar& var() const { return var_; }
   bool success() const { return success_; }
   bool conversion_completed() const { return conversion_completed_; }
 
  private:
   ScopedPPVar var_;
   bool success_;
   bool conversion_completed_;
 };
 
-// static
-gin::WrapperInfo MessageChannel::kWrapperInfo = {gin::kEmbedderNativeGin};
+MessageChannel::MessageChannelNPObject::MessageChannelNPObject() {}
 
-// static
-MessageChannel* MessageChannel::Create(PepperPluginInstanceImpl* instance,
-                                       v8::Persistent<v8::Object>* result) {
-  MessageChannel* message_channel = new MessageChannel(instance);
-  v8::HandleScope handle_scope(instance->GetIsolate());
-  v8::Context::Scope context_scope(instance->GetContext());
-  gin::Handle<MessageChannel> handle =
-      gin::CreateHandle(instance->GetIsolate(), message_channel);
-  result->Reset(instance->GetIsolate(), handle.ToV8()->ToObject());
-  return message_channel;
+MessageChannel::MessageChannelNPObject::~MessageChannelNPObject() {}
+
+MessageChannel::MessageChannel(PepperPluginInstanceImpl* instance)
+    : instance_(instance),
+      passthrough_object_(NULL),
+      np_object_(NULL),
+      early_message_queue_state_(QUEUE_MESSAGES),
+      weak_ptr_factory_(this) {
+  // Now create an NPObject for receiving calls to postMessage. This sets the
+  // reference count to 1.  We release it in the destructor.
+  NPObject* obj = WebBindings::createObject(instance_->instanceNPP(),
+                                            &message_channel_class);
+  DCHECK(obj);
+  np_object_ = static_cast<MessageChannel::MessageChannelNPObject*>(obj);
+  np_object_->message_channel = weak_ptr_factory_.GetWeakPtr();
 }
 
 MessageChannel::~MessageChannel() {
-  passthrough_object_.Reset();
+  WebBindings::releaseObject(np_object_);
+  if (passthrough_object_)
+    WebBindings::releaseObject(passthrough_object_);
 }
 
-void MessageChannel::InstanceDeleted() {
-  instance_ = NULL;
+void MessageChannel::Start() {
+  // We PostTask here instead of draining the message queue directly
+  // since we haven't finished initializing the PepperWebPluginImpl yet, so
+  // the plugin isn't available in the DOM.
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MessageChannel::DrainEarlyMessageQueue,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void MessageChannel::SetPassthroughObject(NPObject* passthrough) {
+  // Retain the passthrough object; We need to ensure it lives as long as this
+  // MessageChannel.
+  if (passthrough)
+    WebBindings::retainObject(passthrough);
+
+  // If we had a passthrough set already, release it. Note that we retain the
+  // incoming passthrough object first, so that we behave correctly if anyone
+  // invokes:
+  //   SetPassthroughObject(passthrough_object());
+  if (passthrough_object_)
+    WebBindings::releaseObject(passthrough_object_);
+
+  passthrough_object_ = passthrough;
+}
+
+bool MessageChannel::GetReadOnlyProperty(NPIdentifier key,
+                                         NPVariant* value) const {
+  std::map<NPIdentifier, ScopedPPVar>::const_iterator it =
+      internal_properties_.find(key);
+  if (it != internal_properties_.end()) {
+    if (value)
+      return PPVarToNPVariant(it->second.get(), value);
+    return true;
+  }
+  return false;
+}
+
+void MessageChannel::SetReadOnlyProperty(PP_Var key, PP_Var value) {
+  internal_properties_[PPVarToNPIdentifier(key)] = ScopedPPVar(value);
 }
 
 void MessageChannel::PostMessageToJavaScript(PP_Var message_data) {
   v8::HandleScope scope(v8::Isolate::GetCurrent());
 
   // Because V8 is probably not on the stack for Native->JS calls, we need to
   // enter the appropriate context for the plugin.
-  v8::Local<v8::Context> context = instance_->GetContext();
+  WebPluginContainer* container = instance_->container();
+  // It's possible that container() is NULL if the plugin has been removed from
+  // the DOM (but the PluginInstance is not destroyed yet).
+  if (!container)
+    return;
+
+  v8::Local<v8::Context> context =
+      container->element().document().frame()->mainWorldScriptContext();
+  // If the page is being destroyed, the context may be empty.
   if (context.IsEmpty())
     return;
-
   v8::Context::Scope context_scope(context);
 
   v8::Handle<v8::Value> v8_val;
   if (!V8VarConverter(instance_->pp_instance())
            .ToV8Value(message_data, context, &v8_val)) {
     PpapiGlobals::Get()->LogWithSource(instance_->pp_instance(),
                                        PP_LOGLEVEL_ERROR,
                                        std::string(),
                                        kVarToV8ConversionError);
     return;
   }
 
   WebSerializedScriptValue serialized_val =
       WebSerializedScriptValue::serialize(v8_val);
 
   if (early_message_queue_state_ != SEND_DIRECTLY) {
     // We can't just PostTask here; the messages would arrive out of
     // order. Instead, we queue them up until we're ready to post
     // them.
     early_message_queue_.push_back(serialized_val);
   } else {
     // The proxy sent an asynchronous message, so the plugin is already
     // unblocked. Therefore, there's no need to PostTask.
     DCHECK(early_message_queue_.empty());
     PostMessageToJavaScriptImpl(serialized_val);
   }
 }
 
-void MessageChannel::Start() {
-  // We PostTask here instead of draining the message queue directly
-  // since we haven't finished initializing the PepperWebPluginImpl yet, so
-  // the plugin isn't available in the DOM.
-  base::MessageLoop::current()->PostTask(
-      FROM_HERE,
-      base::Bind(&MessageChannel::DrainEarlyMessageQueue,
-                 weak_ptr_factory_.GetWeakPtr()));
-}
-
-void MessageChannel::SetPassthroughObject(v8::Handle<v8::Object> passthrough) {
-  passthrough_object_.Reset(instance_->GetIsolate(), passthrough);
-}
-
-void MessageChannel::SetReadOnlyProperty(PP_Var key, PP_Var value) {
-  StringVar* key_string = StringVar::FromPPVar(key);
-  if (key_string) {
-    internal_named_properties_[key_string->value()] = ScopedPPVar(value);
-  } else {
-    NOTREACHED();
-  }
-}
-
-MessageChannel::MessageChannel(PepperPluginInstanceImpl* instance)
-    : gin::NamedPropertyInterceptor(instance->GetIsolate(), this),
-      instance_(instance),
-      early_message_queue_state_(QUEUE_MESSAGES),
-      weak_ptr_factory_(this) {
-}
-
-gin::ObjectTemplateBuilder MessageChannel::GetObjectTemplateBuilder(
-    v8::Isolate* isolate) {
-  return Wrappable<MessageChannel>::GetObjectTemplateBuilder(isolate)
-      .AddNamedPropertyInterceptor();
-}
-
-v8::Local<v8::Value> MessageChannel::GetNamedProperty(
-    v8::Isolate* isolate,
-    const std::string& identifier) {
-  if (!instance_)
-    return v8::Local<v8::Value>();
-
-  PepperTryCatchV8 try_catch(instance_, V8VarConverter::kDisallowObjectVars,
-                             isolate);
-  if (identifier == kPostMessage) {
-    return gin::CreateFunctionTemplate(isolate,
-        base::Bind(&MessageChannel::PostMessageToNative,
-                   weak_ptr_factory_.GetWeakPtr()))->GetFunction();
-  } else if (identifier == kPostMessageAndAwaitResponse && HasDevPermission()) {
-    return gin::CreateFunctionTemplate(isolate,
-        base::Bind(&MessageChannel::PostBlockingMessageToNative,
-                   weak_ptr_factory_.GetWeakPtr()))->GetFunction();
-  }
-
-  std::map<std::string, ScopedPPVar>::const_iterator it =
-      internal_named_properties_.find(identifier);
-  if (it != internal_named_properties_.end()) {
-    v8::Handle<v8::Value> result = try_catch.ToV8(it->second.get());
-    if (try_catch.ThrowException())
-      return v8::Local<v8::Value>();
-    return result;
-  }
-
-  PluginObject* plugin_object = GetPluginObject(isolate);
-  if (plugin_object)
-    return plugin_object->GetNamedProperty(isolate, identifier);
-  return v8::Local<v8::Value>();
-}
-
-bool MessageChannel::SetNamedProperty(v8::Isolate* isolate,
-                                      const std::string& identifier,
-                                      v8::Local<v8::Value> value) {
-  if (!instance_)
-    return false;
-  PepperTryCatchV8 try_catch(instance_, V8VarConverter::kDisallowObjectVars,
-                             isolate);
-  if (identifier == kPostMessage ||
-      (identifier == kPostMessageAndAwaitResponse && HasDevPermission())) {
-    try_catch.ThrowException("Cannot set properties with the name postMessage"
-                             "or postMessageAndAwaitResponse");
-    return true;
-  }
-
-  // We don't forward this to the passthrough object; no plugins use that
-  // feature.
-  // TODO(raymes): Remove SetProperty support from PPP_Class.
-
-  return false;
-}
-
-std::vector<std::string> MessageChannel::EnumerateNamedProperties(
-    v8::Isolate* isolate) {
-  std::vector<std::string> result;
-  PluginObject* plugin_object = GetPluginObject(isolate);
-  if (plugin_object)
-    result = plugin_object->EnumerateNamedProperties(isolate);
-  result.push_back(kPostMessage);
-  if (HasDevPermission())
-    result.push_back(kPostMessageAndAwaitResponse);
-  return result;
-}
-
-void MessageChannel::PostMessageToNative(gin::Arguments* args) {
-  if (!instance_)
-    return;
-  if (args->Length() != 1) {
-    // TODO(raymes): Consider throwing an exception here. We don't now for
-    // backward compatibility.
-    return;
-  }
-
-  v8::Handle<v8::Value> message_data;
-  if (!args->GetNext(&message_data)) {
-    NOTREACHED();
-  }
-
+void MessageChannel::PostMessageToNative(const NPVariant* message_data) {
   EnqueuePluginMessage(message_data);
   DrainCompletedPluginMessages();
 }
 
-void MessageChannel::PostBlockingMessageToNative(gin::Arguments* args) {
-  if (!instance_)
-    return;
-  PepperTryCatchV8 try_catch(instance_, V8VarConverter::kDisallowObjectVars,
-                             args->isolate());
-  if (args->Length() != 1) {
-    try_catch.ThrowException(
-        "postMessageAndAwaitResponse requires one argument");
-    return;
-  }
-
-  v8::Handle<v8::Value> message_data;
-  if (!args->GetNext(&message_data)) {
-    NOTREACHED();
-  }
-
+void MessageChannel::PostBlockingMessageToNative(const NPVariant* message_data,
+                                                 NPVariant* np_result) {
   if (early_message_queue_state_ == QUEUE_MESSAGES) {
-    try_catch.ThrowException(
+    WebBindings::setException(
+        np_object_,
         "Attempted to call a synchronous method on a plugin that was not "
         "yet loaded.");
     return;
   }
 
   // If the queue of messages to the plugin is non-empty, we're still waiting on
   // pending Var conversions. This means at some point in the past, JavaScript
   // called postMessage (the async one) and passed us something with a browser-
   // side host (e.g., FileSystem) and we haven't gotten a response from the
   // browser yet. We can't currently support sending a sync message if the
   // plugin does this, because it will break the ordering of the messages
   // arriving at the plugin.
   // TODO(dmichael): Fix this.
   // See https://code.google.com/p/chromium/issues/detail?id=367896#c4
   if (!plugin_message_queue_.empty()) {
-    try_catch.ThrowException(
+    WebBindings::setException(
+        np_object_,
         "Failed to convert parameter synchronously, because a prior "
         "call to postMessage contained a type which required asynchronous "
         "transfer which has not completed. Not all types are supported yet by "
         "postMessageAndAwaitResponse. See crbug.com/367896.");
     return;
   }
-  ScopedPPVar param = try_catch.FromV8(message_data);
-  if (try_catch.ThrowException())
-    return;
-
+  ScopedPPVar param;
+  if (message_data->type == NPVariantType_Object) {
+    // Convert NPVariantType_Object in to an appropriate PP_Var like Dictionary,
+    // Array, etc. Note NPVariantToVar would convert to an "Object" PP_Var,
+    // which we don't support for Messaging.
+    v8::Handle<v8::Value> v8_value = WebBindings::toV8Value(message_data);
+    V8VarConverter v8_var_converter(instance_->pp_instance());
+    bool success = v8_var_converter.FromV8ValueSync(
+        v8_value,
+        v8::Isolate::GetCurrent()->GetCurrentContext(),
+        &param);
+    if (!success) {
+      WebBindings::setException(
+          np_object_,
+          "Failed to convert the given parameter to a PP_Var to send to "
+          "the plugin.");
+      return;
+    }
+  } else {
+    param = ScopedPPVar(ScopedPPVar::PassRef(),
+                        NPVariantToPPVar(instance(), message_data));
+  }
   ScopedPPVar pp_result;
   bool was_handled = instance_->HandleBlockingMessage(param, &pp_result);
   if (!was_handled) {
-    try_catch.ThrowException(
+    WebBindings::setException(
+        np_object_,
         "The plugin has not registered a handler for synchronous messages. "
         "See the documentation for PPB_Messaging::RegisterMessageHandler "
         "and PPP_MessageHandler.");
     return;
   }
-  v8::Handle<v8::Value> v8_result = try_catch.ToV8(pp_result.get());
-  if (try_catch.ThrowException())
+  v8::Handle<v8::Value> v8_val;
+  if (!V8VarConverter(instance_->pp_instance()).ToV8Value(
+          pp_result.get(),
+          v8::Isolate::GetCurrent()->GetCurrentContext(),
+          &v8_val)) {
+    WebBindings::setException(
+        np_object_,
+        "Failed to convert the plugin's result to a JavaScript type.");
     return;
-
-  args->Return(v8_result);
+  }
+  // Success! Convert the result to an NPVariant.
+  WebBindings::toNPVariant(v8_val, NULL, np_result);
 }
 
 void MessageChannel::PostMessageToJavaScriptImpl(
     const WebSerializedScriptValue& message_data) {
   DCHECK(instance_);
 
   WebPluginContainer* container = instance_->container();
   // It's possible that container() is NULL if the plugin has been removed from
   // the DOM (but the PluginInstance is not destroyed yet).
   if (!container)
@@ skipping 13 matching lines @@
   //     sent messages, while |source| is only specified for cross-document
   //     messages:
   //      http://www.whatwg.org/specs/web-apps/current-work/multipage/comms.html
   //     This currently behaves like Web Workers. On Firefox, Chrome, and Safari
   //     at least, postMessage on Workers does not provide the origin or source.
   //     TODO(dmichael):  Add origin if we change to a more iframe-like origin
   //                      policy (see crbug.com/81537)
   container->element().dispatchEvent(msg_event);
 }
 
-PluginObject* MessageChannel::GetPluginObject(v8::Isolate* isolate) {
-  return PluginObject::FromV8Object(isolate,
-      v8::Local<v8::Object>::New(isolate, passthrough_object_));
-}
+void MessageChannel::EnqueuePluginMessage(const NPVariant* variant) {
+  plugin_message_queue_.push_back(VarConversionResult());
+  if (variant->type == NPVariantType_Object) {
+    // Convert NPVariantType_Object in to an appropriate PP_Var like Dictionary,
+    // Array, etc. Note NPVariantToVar would convert to an "Object" PP_Var,
+    // which we don't support for Messaging.
 
-void MessageChannel::EnqueuePluginMessage(v8::Handle<v8::Value> v8_value) {
-  plugin_message_queue_.push_back(VarConversionResult());
-  // Convert NPVariantType_Object in to an appropriate PP_Var like Dictionary,
-  // Array, etc. Note NPVariantToVar would convert to an "Object" PP_Var,
-  // which we don't support for Messaging.
-  // TODO(raymes): Possibly change this to use TryCatch to do the conversion and
-  // throw an exception if necessary.
-  V8VarConverter v8_var_converter(instance_->pp_instance());
-  V8VarConverter::VarResult conversion_result =
-      v8_var_converter.FromV8Value(
-          v8_value,
-          v8::Isolate::GetCurrent()->GetCurrentContext(),
-          base::Bind(&MessageChannel::FromV8ValueComplete,
-                     weak_ptr_factory_.GetWeakPtr(),
-                     &plugin_message_queue_.back()));
-  if (conversion_result.completed_synchronously) {
+    // Calling WebBindings::toV8Value creates a wrapper around NPVariant so it
+    // won't result in a deep copy.
+    v8::Handle<v8::Value> v8_value = WebBindings::toV8Value(variant);
+    V8VarConverter v8_var_converter(instance_->pp_instance());
+    V8VarConverter::VarResult conversion_result =
+        v8_var_converter.FromV8Value(
+            v8_value,
+            v8::Isolate::GetCurrent()->GetCurrentContext(),
+            base::Bind(&MessageChannel::FromV8ValueComplete,
+                       weak_ptr_factory_.GetWeakPtr(),
+                       &plugin_message_queue_.back()));
+    if (conversion_result.completed_synchronously) {
+      plugin_message_queue_.back().ConversionCompleted(
+          conversion_result.var,
+          conversion_result.success);
+    }
+  } else {
     plugin_message_queue_.back().ConversionCompleted(
-        conversion_result.var,
-        conversion_result.success);
+        ScopedPPVar(ScopedPPVar::PassRef(),
+                    NPVariantToPPVar(instance(), variant)),
+        true);
+    DCHECK(plugin_message_queue_.back().var().get().type != PP_VARTYPE_OBJECT);
   }
 }
 
 void MessageChannel::FromV8ValueComplete(VarConversionResult* result_holder,
                                          const ScopedPPVar& result,
                                          bool success) {
-  if (!instance_)
-    return;
   result_holder->ConversionCompleted(result, success);
   DrainCompletedPluginMessages();
 }
 
 void MessageChannel::DrainCompletedPluginMessages() {
-  DCHECK(instance_);
   if (early_message_queue_state_ == QUEUE_MESSAGES)
     return;
 
   while (!plugin_message_queue_.empty() &&
          plugin_message_queue_.front().conversion_completed()) {
     const VarConversionResult& front = plugin_message_queue_.front();
     if (front.success()) {
       instance_->HandleMessage(front.var());
     } else {
       PpapiGlobals::Get()->LogWithSource(instance()->pp_instance(),
                                          PP_LOGLEVEL_ERROR,
                                          std::string(),
                                          kV8ToVarConversionError);
     }
     plugin_message_queue_.pop_front();
   }
 }
 
 void MessageChannel::DrainEarlyMessageQueue() {
-  if (!instance_)
-    return;
   DCHECK(early_message_queue_state_ == QUEUE_MESSAGES);
 
   // Take a reference on the PluginInstance. This is because JavaScript code
   // may delete the plugin, which would destroy the PluginInstance and its
   // corresponding MessageChannel.
   scoped_refptr<PepperPluginInstanceImpl> instance_ref(instance_);
   while (!early_message_queue_.empty()) {
     PostMessageToJavaScriptImpl(early_message_queue_.front());
     early_message_queue_.pop_front();
   }
   early_message_queue_state_ = SEND_DIRECTLY;
 
   DrainCompletedPluginMessages();
 }
 
 }  // namespace content