Add support for snapshot loading to Sky

sky/engine/core/script/dart_controller.cc

Index: sky/engine/core/script/dart_controller.cc
diff --git a/sky/engine/core/script/dart_controller.cc b/sky/engine/core/script/dart_controller.cc
index 80338ba8a09fae1cd1814509ad918776c44510c9..ea06ed2836b661fabccdd38d791b60e22e5ae575 100644
--- a/sky/engine/core/script/dart_controller.cc
+++ b/sky/engine/core/script/dart_controller.cc
@@ -27,6 +27,7 @@
 #include "sky/engine/core/script/dart_dependency_catcher.h"
 #include "sky/engine/core/script/dart_loader.h"
 #include "sky/engine/core/script/dart_service_isolate.h"
+#include "sky/engine/core/script/dart_snapshot_loader.h"
 #include "sky/engine/core/script/dom_dart_state.h"
 #include "sky/engine/public/platform/Platform.h"
 #include "sky/engine/tonic/dart_api_scope.h"
@@ -133,6 +134,26 @@ void DartController::LoadMainLibrary(const KURL& url, mojo::URLResponsePtr respo
                              base::Bind(&DartController::DidLoadMainLibrary, weak_factory_.GetWeakPtr(), url));
 }
 
+void DartController::DidLoadSnapshot() {
+  DCHECK(Dart_CurrentIsolate() == nullptr);
+  snapshot_loader_ = nullptr;
+
+  Dart_Isolate isolate = dart_state()->isolate();
+  DartIsolateScope isolate_scope(isolate);
+  DartApiScope dart_api_scope;
+
+  Dart_Handle library = Dart_RootLibrary();
+  if (LogIfError(library))
+    return;
+  DartInvokeAppField(library, ToDart("main"), 0, nullptr);
+}
+
+void DartController::LoadSnapshot(const KURL& url, mojo::URLResponsePtr response) {
+  snapshot_loader_ = adoptPtr(new DartSnapshotLoader(dart_state()));
+  snapshot_loader_->LoadSnapshot(url, response.Pass(),
+      base::Bind(&DartController::DidLoadSnapshot, weak_factory_.GetWeakPtr()));
+}
+
 void DartController::LoadScriptInModule(
     AbstractModule* module,
     const String& source,
@@ -289,9 +310,11 @@ static Dart_Isolate IsolateCreateCallback(const char* script_uri,
     Builtin::SetNativeResolver(Builtin::kMojoInternalLibrary);
     Builtin::SetNativeResolver(Builtin::kIOLibrary);
 
-    // Ensure the isolate has a root library.
-    Dart_LoadScript(Dart_NewStringFromCString("dart:empty"),
-                    Dart_NewStringFromCString(""), 0, 0);
+    if (!script_uri) {
+      // Ensure the isolate has a root library.

[eseidel, 2015/06/23 06:21:39]

I don't think this is necessary anymore  This was for when we had .sky files. So
I guess we still need it, but not in the SkyView case.

I think if we remove it we have to use a different loading function.

[abarth-chromium, 2015/06/23 14:50:42]

Yeah, I was close to removing it entirely.  I think it's only needed for one of
the oddball isolates.  I can try again to remove it entirely, but for now I'll
add a comment explaining.

[eseidel, 2015/06/23 16:02:03]

My recollection was it was needed because of the way we did library creation (to
allow mutiple libraries in a single .sky file).

+      Dart_LoadScript(Dart_NewStringFromCString("dart:empty"),
+                      Dart_EmptyString(), 0, 0);
+    }
   }
 
   Dart_ExitIsolate();
@@ -334,10 +357,6 @@ void DartController::CreateIsolateFor(PassOwnPtr<DOMDartState> state) {
   {
     DartApiScope apiScope;
 
-    // Ensure the isolate has a root library.
-    Dart_LoadScript(Dart_NewStringFromCString("dart:empty"),
-                    Dart_NewStringFromCString(""), 0, 0);
-
     Builtin::SetNativeResolver(Builtin::kBuiltinLibrary);
     Builtin::SetNativeResolver(Builtin::kMojoInternalLibrary);
     Builtin::SetNativeResolver(Builtin::kIOLibrary);