Enable Dart's checked mode in the Sky controller by default for debug builds

This matches the behaviour of the Mojo Dart controller and was requested by tonyg@

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1152873006

engine/config.gni

@@ -21,6 +21,13 @@ declare_args() {
 
   # Experimental support for the Dart VM.
   sky_use_dart = false
+
+  # Default to strict mode in debug builds.
+  if (is_debug) {
+    sky_dart_strict_mode = true
+  } else {
+    sky_dart_strict_mode = false
+  }
 }
 
 # feature_defines_list ---------------------------------------------------------
@@ -42,6 +49,10 @@ if (sky_asserts_always_on) {
   feature_defines_list += [ "ENABLE_ASSERT=1" ]
 }
 
+if (sky_dart_strict_mode) {
+  feature_defines_list += [ "ENABLE_DART_STRICT=1" ]
+}
+
 if (sky_use_dart) {
   feature_defines_list += [ "WTF_USE_DART=1" ]
 }

engine/core/script/dart_controller.cc

@@ -41,7 +41,7 @@
 
 namespace blink {
 
-#if ENABLE(ASSERT)
+#if ENABLE(DART_STRICT)
 static const char* kCheckedModeArgs[] = {
   "--enable_asserts",
   "--enable_type_checks",
@@ -369,7 +369,7 @@ void DartController::InitVM() {
   int argc = 0;
   const char** argv = nullptr;
 
-#if ENABLE(ASSERT)
+#if ENABLE(DART_STRICT)
   argc = arraysize(kCheckedModeArgs);
   argv = kCheckedModeArgs;
 #endif