Introduce Sky packaged apps.

sky/engine/core/script/dart_loader.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sky/engine/config.h"
 #include "sky/engine/core/script/dart_loader.h"
 
 #include "base/callback.h"
 #include "base/trace_event/trace_event.h"
 #include "mojo/common/data_pipe_drainer.h"
 #include "sky/engine/core/script/dart_dependency_catcher.h"
 #include "sky/engine/core/script/dom_dart_state.h"
 #include "sky/engine/platform/fetcher/MojoFetcher.h"
 #include "sky/engine/platform/weborigin/KURL.h"
 #include "sky/engine/tonic/dart_api_scope.h"
 #include "sky/engine/tonic/dart_converter.h"
 #include "sky/engine/tonic/dart_error.h"
 #include "sky/engine/tonic/dart_isolate_scope.h"
 #include "sky/engine/wtf/MainThread.h"
 
 using mojo::common::DataPipeDrainer;
 
 namespace blink {
 namespace {
 
 Dart_Handle CanonicalizeURL(DartState* state,
                             Dart_Handle library,
                             Dart_Handle url) {
   String string = StringFromDart(url);
+
   if (string.startsWith("dart:") || string.startsWith("mojo:"))
     return url;
   // TODO(dart): Figure out how 'package:' should work in sky.
   if (string.startsWith("package:")) {
-    string.replace("package:", "/packages/");
+    KURL baseUri = DOMDartState::Current()->document()->baseURI();
+    bool is_packaged_app = baseUri.string().startsWith("file://");

[eseidel, 2015/04/14 17:06:31]

Why aren't packaged apps just served over http locally?  That seems like it
would require the least amount of code modification?

+
+    if (is_packaged_app) {
+      // In packaged apps, |package:<foo>| is specified relative to the base URL
+      // of the application.
+      string.replace("package:", "");
+      string = KURL(baseUri, string).string();
+    } else {
+      string.replace("package:", "/packages/");
+    }
   }
+
   String library_url_string = StringFromDart(Dart_LibraryUrl(library));
   KURL library_url = KURL(ParsedURLString, library_url_string);
   KURL resolved_url = KURL(library_url, string);
   return StringToDart(state, resolved_url.string());
 }
 
 }  // namespace
 
 // A DartLoader::Job represents a network load. It fetches data from the network
 // and buffers the data in Vector. To cancel the job, delete this object.
 class DartLoader::Job : public DartDependency,
                         public MojoFetcher::Client,
                         public DataPipeDrainer::Client {
  public:
   Job(DartLoader* loader, const KURL& url)
       : loader_(loader), url_(url), fetcher_(this, url) {}
 
   const KURL& url() const { return url_; }
 
  protected:
   DartLoader* loader_;
   // TODO(abarth): Should we be using SharedBuffer to buffer the data?
   Vector<uint8_t> buffer_;
 
  private:
   // MojoFetcher::Client
   void OnReceivedResponse(mojo::URLResponsePtr response) override {
-    if (response->status_code != 200) {
+    bool failed_load = response->status_code != 200;
+
+    // TODO(blundell): Why are successful loads of file:// URLs returning a 
+    // status code of 0?
+    if (response->status_code == 0) {

[eseidel, 2015/04/14 17:06:31]

Here again, instead of teaching Sky to understand a non-networked world, why not
just make packaged apps behave like a network?

+      failed_load = response->error != NULL;
+    }
+    if (failed_load) {
       loader_->DidFailJob(this);
       return;
     }
     drainer_ = adoptPtr(new DataPipeDrainer(this, response->body.Pass()));
   }
 
   // DataPipeDrainer::Client
   void OnDataAvailable(const void* data, size_t num_bytes) override {
     buffer_.append(static_cast<const uint8_t*>(data), num_bytes);
   }
@@ skipping 219 matching lines @@
 
   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