[core] Introduce Timer abstraction

platform/default/timer.cpp

@@ -0,0 +1,40 @@
+#include <mbgl/util/timer.hpp>
+
+#include <mbgl/util/run_loop.hpp>
+#include <mbgl/util/uv_detail.hpp>
+
+namespace mbgl {
+namespace util {
+
+class Timer::Impl {
+public:
+    Impl()
+        : timer(reinterpret_cast<uv_loop_t*>(RunLoop::getLoopHandle())) {
+    }
+
+    uv::timer timer;
+};
+
+Timer::Timer()
+    : impl(std::make_unique<Impl>()) {
+}
+
+Timer::~Timer() {
+}
+
+void Timer::start(Duration timeout, Duration repeat, std::function<void()>&& cb) {
+    impl->timer.start(std::chrono::duration_cast<std::chrono::milliseconds>(timeout).count(),
+                      std::chrono::duration_cast<std::chrono::milliseconds>(repeat).count(),
+                      std::move(cb));
+}
+
+void Timer::stop() {
+    impl->timer.stop();
+}
+
+void Timer::unref() {
+    impl->timer.unref();
+}
+
+}
+}