Improve DartLoader error handling.

sky/engine/core/script/dart_loader.cc

Index: sky/engine/core/script/dart_loader.cc
diff --git a/sky/engine/core/script/dart_loader.cc b/sky/engine/core/script/dart_loader.cc
index 4345dda3c099db161affa41fedbc171cf2a83df4..95ac8dc0442a3bc86565c0af25244911d50a8ef2 100644
--- a/sky/engine/core/script/dart_loader.cc
+++ b/sky/engine/core/script/dart_loader.cc
@@ -59,6 +59,10 @@ class DartLoader::Job : public DartDependency,
  private:
   // MojoFetcher::Client
   void OnReceivedResponse(mojo::URLResponsePtr response) override {
+    if (response->status_code != 200) {
+      loader_->DidFailJob(this);
+      return;
+    }
     // TODO(abarth): Handle network errors.
     drainer_ = adoptPtr(new DataPipeDrainer(this, response->body.Pass()));
   }
@@ -81,7 +85,9 @@ class DartLoader::ImportJob : public Job {
  private:
   // DataPipeDrainer::Client
   void OnDataComplete() override {
-    loader_->DidCompleteImportJob(this, buffer_);
+    // DataPipeDrainer calls OnDataComplete regardless of errors.
+    if (!loader_->saw_error())
+      loader_->DidCompleteImportJob(this, buffer_);
   }
 };
 
@@ -95,7 +101,9 @@ class DartLoader::SourceJob : public Job {
  private:
   // DataPipeDrainer::Client
   void OnDataComplete() override {
-    loader_->DidCompleteSourceJob(this, buffer_);
+    // DataPipeDrainer calls OnDataComplete regardless of errors.
+    if (!loader_->saw_error())

[abarth-chromium, 2015/02/13 23:50:29]

Why do we only do this once for the entire lifetime of the isolate?

+      loader_->DidCompleteSourceJob(this, buffer_);
   }
 
   DartPersistentValue library_;
@@ -175,7 +183,9 @@ class DartLoader::WatcherSignaler {
 };
 
 DartLoader::DartLoader(DartState* dart_state)
-    : dart_state_(dart_state->GetWeakPtr()), dependency_catcher_(nullptr) {
+    : dart_state_(dart_state->GetWeakPtr()),
+      dependency_catcher_(nullptr),
+      saw_error_(false) {
 }
 
 DartLoader::~DartLoader() {
@@ -231,6 +241,7 @@ Dart_Handle DartLoader::Source(Dart_Handle library, Dart_Handle url) {
 
 void DartLoader::DidCompleteImportJob(ImportJob* job,
                                       const Vector<uint8_t>& buffer) {
+  DCHECK(!saw_error_);
   DCHECK(dart_state_);
   DartIsolateScope scope(dart_state_->isolate());
   DartApiScope api_scope;
@@ -248,6 +259,7 @@ void DartLoader::DidCompleteImportJob(ImportJob* job,
 
 void DartLoader::DidCompleteSourceJob(SourceJob* job,
                                       const Vector<uint8_t>& buffer) {
+  DCHECK(!saw_error_);
   DCHECK(dart_state_);
   DartIsolateScope scope(dart_state_->isolate());
   DartApiScope api_scope;
@@ -262,4 +274,19 @@ void DartLoader::DidCompleteSourceJob(SourceJob* job,
   jobs_.remove(job);
 }
 
+void DartLoader::DidFailJob(Job* job) {
+  DCHECK(!saw_error_);
+  saw_error_ = true;
+  DCHECK(dart_state_);
+  DartIsolateScope scope(dart_state_->isolate());
+  DartApiScope api_scope;
+
+  WatcherSignaler watcher_signaler(*this, job);
+
+  LOG(ERROR) << "Library Load failed: " << job->url().string().utf8().data();
+  // TODO(eseidel): Call Dart_LibraryHandleError in the SourceJob case?
+
+  jobs_.remove(job);
+}
+
 }  // namespace blink