[Extensions] Make port creation synchronous in unload handlers

extensions/renderer/messaging_bindings.cc

 // 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.
 
 #include "extensions/renderer/messaging_bindings.h"
 
 #include <stdint.h>
 
 #include <map>
 #include <string>
@@ skipping 251 matching lines @@
   RouteFunction("OpenChannelToNativeApp", "runtime.connectNative",
                 base::Bind(&MessagingBindings::OpenChannelToNativeApp,
                            base::Unretained(this)));
   RouteFunction(
       "OpenChannelToTab",
       base::Bind(&MessagingBindings::OpenChannelToTab, base::Unretained(this)));
 }
 
 MessagingBindings::~MessagingBindings() {
   g_messaging_map.Get().erase(context());
+  if (ports_created_normal_ > 0 || ports_created_in_before_unload_ > 0 ||
+      ports_created_in_unload_ > 0) {
+    UMA_HISTOGRAM_COUNTS_100(
+        "Extensions.Messaging.ExtensionPortsCreated.InBeforeUnload",
+        ports_created_in_before_unload_);
+    UMA_HISTOGRAM_COUNTS_100(
+        "Extensions.Messaging.ExtensionPortsCreated.InUnload",
+        ports_created_in_unload_);
+    UMA_HISTOGRAM_COUNTS_100(
+        "Extensions.Messaging.ExtensionPortsCreated.Normal",
+        ports_created_normal_);
+  }
 }
 
 // static
 void MessagingBindings::ValidateMessagePort(
     const ScriptContextSet& context_set,
     int global_port_id,
     content::RenderFrame* render_frame) {
   int routing_id = render_frame->GetRoutingID();
 
   bool has_port = false;
@@ skipping 161 matching lines @@
 
   info.target_id = *v8::String::Utf8Value(args[0]);
   info.source_url = context()->url();
   std::string channel_name = *v8::String::Utf8Value(args[1]);
   // TODO(devlin): Why is this not part of info?
   bool include_tls_channel_id =
       args.Length() > 2 ? args[2]->BooleanValue() : false;
 
   ExtensionFrameHelper* frame_helper = ExtensionFrameHelper::Get(render_frame);
   DCHECK(frame_helper);
-  frame_helper->RequestPortId(
-      info, channel_name, include_tls_channel_id,
-      base::Bind(&MessagingBindings::SetGlobalPortId,
-                 weak_ptr_factory_.GetWeakPtr(), local_id));
+
+  blink::WebLocalFrame* web_frame = render_frame->GetWebFrame();
+  // If the frame is unloading, we need to assign the port id synchronously to
+  // avoid dropping the message on the floor; see crbug.com/660706.
+  // TODO(devlin): Investigate whether we need to continue supporting this long-
+  // term, and, if so, find an alternative that doesn't require synchronous
+  // IPCs.
+  if (!web_frame->document().isNull() &&
+      (web_frame->document().unloadStarted() ||
+       web_frame->document().processingBeforeUnload())) {
+    ports_created_in_before_unload_ +=
+        web_frame->document().processingBeforeUnload() ? 1 : 0;
+    ports_created_in_unload_ += web_frame->document().unloadStarted() ? 1 : 0;
+    int global_id = frame_helper->RequestSyncPortId(info, channel_name,
+                                                    include_tls_channel_id);
+    ports_[local_id]->SetGlobalId(global_id);
+  } else {
+    ++ports_created_normal_;
+    frame_helper->RequestPortId(
+        info, channel_name, include_tls_channel_id,
+        base::Bind(&MessagingBindings::SetGlobalPortId,
+                   weak_ptr_factory_.GetWeakPtr(), local_id));
+  }
 
   args.GetReturnValue().Set(static_cast<int32_t>(local_id));
 }
 
 void MessagingBindings::OpenChannelToNativeApp(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   // The Javascript code should validate/fill the arguments.
   CHECK_EQ(args.Length(), 1);
   CHECK(args[0]->IsString());
   // This should be checked by our function routing code.
@@ skipping 86 matching lines @@
   DCHECK(iter != disconnected_ports_.end());
   iter->second->SetGlobalId(global_id);
   // Setting the global id dispatches pending messages, so we can delete the
   // port now.
   disconnected_ports_.erase(iter);
 }
 
 int MessagingBindings::GetNextLocalId() { return next_local_id_++; }
 
 }  // namespace extensions