Fix build, OnHandleReady signature change (#3874)

content_handler/vulkan_rasterizer.cc

@@ -306,7 +306,8 @@ void VulkanRasterizer::VulkanSurfaceProducer::Tick() {
 
 void VulkanRasterizer::VulkanSurfaceProducer::OnHandleReady(
     mx_handle_t handle,
-    mx_signals_t pending) {
+    mx_signals_t pending,
+    uint64_t count) {
   FTL_DCHECK(pending & MX_EPAIR_PEER_CLOSED);
 
   auto it = pending_surfaces_.find(handle);

content_handler/vulkan_rasterizer.h

@@ -49,7 +49,9 @@ class VulkanRasterizer : public Rasterizer {
 
    private:
     // |mtl::MessageLoopHandler|
-    void OnHandleReady(mx_handle_t handle, mx_signals_t pending) override;
+    void OnHandleReady(mx_handle_t handle,
+                       mx_signals_t pending,
+                       uint64_t count) override;
 
     struct Surface {
       sk_sp<GrVkBackendContext> backend_context;