Add callback for error notifications on renderStill()

The callback will be called when any of the resources requested
from the network failed to load.

There is not recovery implemented yet, so the closest thing to
reseting the Map object and reloading all the resources would
be setting a new style.

2 files changed, 3 insertions, 3 deletions

diff --git a/test/api/repeated_render.cpp b/test/api/repeated_render.cpp
index ce7e6cbb0b..f563b00071 100644
--- a/test/api/repeated_render.cpp
+++ b/test/api/repeated_render.cpp
@@ -28,7 +28,7 @@ TEST(API, RepeatedRender) {
         map.resize(128, 512, 1);
         map.setStyleJSON(style, "test/suite");
         std::promise<std::unique_ptr<const StillImage>> promise;
-        map.renderStill([&promise](std::unique_ptr<const StillImage> image) {
+        map.renderStill([&promise](std::exception_ptr, std::unique_ptr<const StillImage> image) {
             promise.set_value(std::move(image));
         });
         auto result = promise.get_future().get();
@@ -42,7 +42,7 @@ TEST(API, RepeatedRender) {
         map.resize(512, 512, 2);
         map.setStyleJSON(style, "TEST_DATA/suite");
         std::promise<std::unique_ptr<const StillImage>> promise;
-        map.renderStill([&promise](std::unique_ptr<const StillImage> image) {
+        map.renderStill([&promise](std::exception_ptr, std::unique_ptr<const StillImage> image) {
             promise.set_value(std::move(image));
         });
         auto result = promise.get_future().get();
diff --git a/test/headless/headless.cpp b/test/headless/headless.cpp
index a02062dbdd..8dfed0383b 100644
--- a/test/headless/headless.cpp
+++ b/test/headless/headless.cpp
@@ -152,7 +152,7 @@ TEST_P(HeadlessTest, render) {
         map.setLatLngZoom(mbgl::LatLng(latitude, longitude), zoom);
         map.setBearing(bearing);
 
-        map.renderStill([&](std::unique_ptr<const StillImage> image) {
+        map.renderStill([&](std::exception_ptr, std::unique_ptr<const StillImage> image) {
             const std::string png = util::compress_png(image->width, image->height, image->pixels.get());
             util::write_file("test/suite/tests/" + base + "/" + name +  "/actual.png", png);
             promise.set_value();