[core] Render from the main thread

Do not create a thread for the MapContext anymore.

platform/node/src/node_map.cpp

@@ -1,10 +1,8 @@
 #include "node_map.hpp"
 #include "node_request.hpp"
-#include "node_mapbox_gl_native.hpp"
 
 #include <mbgl/platform/default/headless_display.hpp>
 #include <mbgl/util/exception.hpp>
-#include <mbgl/util/work_request.hpp>
 
 #include <unistd.h>
 
@@ -474,18 +472,16 @@ NodeMap::~NodeMap() {
     if (valid) release();
 }
 
-std::unique_ptr<mbgl::AsyncRequest> NodeMap::request(const mbgl::Resource& resource, Callback cb1) {
-    // This function can be called from any thread. Make sure we're executing the
-    // JS implementation in the node event loop.
-    return NodeRunLoop().invokeWithCallback([this] (mbgl::Resource res, Callback cb2) {
-        Nan::HandleScope scope;
+std::unique_ptr<mbgl::AsyncRequest> NodeMap::request(const mbgl::Resource& resource, Callback callback_) {
+    Nan::HandleScope scope;
 
-        auto requestHandle = NodeRequest::Create(res, cb2)->ToObject();
-        auto callbackHandle = Nan::New<v8::Function>(NodeRequest::Respond, requestHandle);
+    auto requestHandle = NodeRequest::Create(resource, callback_)->ToObject();
+    auto callbackHandle = Nan::New<v8::Function>(NodeRequest::Respond, requestHandle);
 
-        v8::Local<v8::Value> argv[] = { requestHandle, callbackHandle };
-        Nan::MakeCallback(handle()->GetInternalField(1)->ToObject(), "request", 2, argv);
-    }, cb1, resource);
+    v8::Local<v8::Value> argv[] = { requestHandle, callbackHandle };
+    Nan::MakeCallback(handle()->GetInternalField(1)->ToObject(), "request", 2, argv);
+
+    return std::make_unique<mbgl::AsyncRequest>();
 }
 
 }

platform/node/src/node_mapbox_gl_native.cpp

@@ -5,25 +5,18 @@
 #include <nan.h>
 #pragma GCC diagnostic pop
 
-#include "node_mapbox_gl_native.hpp"
+#include <mbgl/util/run_loop.hpp>
+
 #include "node_map.hpp"
 #include "node_log.hpp"
 #include "node_request.hpp"
 
-namespace node_mbgl {
-
-mbgl::util::RunLoop& NodeRunLoop() {
-    static mbgl::util::RunLoop nodeRunLoop;
-    return nodeRunLoop;
-}
-
-}
-
 void RegisterModule(v8::Local<v8::Object> target, v8::Local<v8::Object> module) {
     // This has the effect of:
     //   a) Ensuring that the static local variable is initialized before any thread contention.
     //   b) unreffing an async handle, which otherwise would keep the default loop running.
-    node_mbgl::NodeRunLoop().stop();
+    static mbgl::util::RunLoop nodeRunLoop;
+    nodeRunLoop.stop();
 
     node_mbgl::NodeMap::Init(target);
     node_mbgl::NodeRequest::Init(target);

platform/node/src/node_mapbox_gl_native.hpp

@@ -1,9 +0,0 @@
-#pragma once
-
-#include <mbgl/util/run_loop.hpp>
-
-namespace node_mbgl {
-
-mbgl::util::RunLoop& NodeRunLoop();
-
-}