Add a flag to sky_viewer to enable checked mode

This flag will let clients who use release builds enable checked mode.

Fixes #22

services/sky/runtime_flags.cc

@@ -16,11 +16,15 @@ RuntimeFlags flags;
 // Load the viewer in testing mode so we can dump pixels.
 const char kTesting[] = "--testing";
 
+// Instruct the DartVM to report type errors.
+const char kEnableCheckedMode[] = "--enable-checked-mode";
+
 }  // namespace
 
 void RuntimeFlags::Initialize(mojo::ApplicationImpl* app) {
   DCHECK(!initialized);
   flags.testing_ = app->HasArg(kTesting);
+  flags.enable_checked_mode_ = app->HasArg(kEnableCheckedMode);
   initialized = true;
 }
 

services/sky/runtime_flags.h

@@ -17,9 +17,11 @@ class RuntimeFlags {
   static const RuntimeFlags& Get();
 
   bool testing() const { return testing_; }
+  bool enable_checked_mode() const { return enable_checked_mode_; }
 
  private:
-  bool testing_;
+  bool testing_ = false;
+  bool enable_checked_mode_ = false;
 };
 
 }  // namespace sky

services/sky/viewer.cc

@@ -37,6 +37,8 @@ class Viewer : public mojo::ApplicationDelegate,
 
     blink::WebRuntimeFeatures::enableObservatory(
         !RuntimeFlags::Get().testing());
+    blink::WebRuntimeFeatures::enableDartCheckedMode(
+        RuntimeFlags::Get().enable_checked_mode());
 
     platform_impl_.reset(new PlatformImpl());
     blink::initialize(platform_impl_.get());

sky/engine/core/script/dart_init.cc

@@ -75,15 +75,16 @@ void CreateEmptyRootLibraryIfNeeded() {
 
 static const char* kDartArgs[] = {
     "--enable_mirrors=false",
-#if ENABLE(DART_STRICT)
-    "--enable_asserts",
-    "--enable_type_checks",
-    "--error_on_bad_type",
-    "--error_on_bad_override",
 #if WTF_OS_IOS || WTF_OS_MACOSX
     "--no-profile"
 #endif
-#endif
+};
+
+static const char* kDartCheckedModeArgs[] = {
+  "--enable_asserts",
+  "--enable_type_checks",
+  "--error_on_bad_type",
+  "--error_on_bad_override",
 };
 
 void UnhandledExceptionCallback(Dart_Handle error) {
@@ -172,7 +173,17 @@ Dart_Isolate IsolateCreateCallback(const char* script_uri,
 void InitDartVM() {
   dart::bin::BootstrapDartIo();
 
-  CHECK(Dart_SetVMFlags(arraysize(kDartArgs), kDartArgs));
+  bool enable_checked_mode = RuntimeEnabledFeatures::dartCheckedModeEnabled();
+#if ENABLE(DART_STRICT)
+  enable_checked_mode = true;
+#endif
+
+  Vector<const char*> args;
+  args.append(kDartArgs, arraysize(kDartArgs));
+  if (enable_checked_mode)
+    args.append(kDartCheckedModeArgs, arraysize(kDartCheckedModeArgs));
+
+  CHECK(Dart_SetVMFlags(args.size(), args.data()));
   // This should be called before calling Dart_Initialize.
   DartDebugger::InitDebugger();
   CHECK(Dart_Initialize(kDartVmIsolateSnapshotBuffer,

sky/engine/platform/RuntimeEnabledFeatures.in

@@ -120,3 +120,4 @@ PseudoClassesInMatchingCriteriaInAuthorShadowTrees status=test
 CredentialManager status=test
 
 Observatory status=stable
+DartCheckedMode

sky/engine/public/web/WebRuntimeFeatures.h

@@ -94,6 +94,8 @@ public:
 
     BLINK_EXPORT static void enableObservatory(bool);
 
+    BLINK_EXPORT static void enableDartCheckedMode(bool);
+
 private:
     WebRuntimeFeatures();
 };

sky/engine/web/WebRuntimeFeatures.cpp

@@ -175,4 +175,9 @@ void WebRuntimeFeatures::enableObservatory(bool enable)
     RuntimeEnabledFeatures::setObservatoryEnabled(enable);
 }
 
+void WebRuntimeFeatures::enableDartCheckedMode(bool enable)
+{
+    RuntimeEnabledFeatures::setDartCheckedModeEnabled(enable);
+}
+
 } // namespace blink