Only reload libraries when they may have been modified.

runtime/bin/loader.cc

Index: runtime/bin/loader.cc
diff --git a/runtime/bin/loader.cc b/runtime/bin/loader.cc
index cf6f4ec7a365c72a097fa60c4778f87deb7a4659..22204788a81b4197e7021f6c7f70665417e66e8d 100644
--- a/runtime/bin/loader.cc
+++ b/runtime/bin/loader.cc
@@ -66,14 +66,16 @@ Loader::~Loader() {
 // Copy the contents of |message| into an |IOResult|.
 void Loader::IOResult::Setup(Dart_CObject* message) {
   ASSERT(message->type == Dart_CObject_kArray);
-  ASSERT(message->value.as_array.length == 4);
+  ASSERT(message->value.as_array.length == 5);
   Dart_CObject* tag_message = message->value.as_array.values[0];
   ASSERT(tag_message != NULL);
   Dart_CObject* uri_message = message->value.as_array.values[1];
   ASSERT(uri_message != NULL);
-  Dart_CObject* library_uri_message = message->value.as_array.values[2];
+  Dart_CObject* resolved_uri_message = message->value.as_array.values[2];
+  ASSERT(resolved_uri_message != NULL);
+  Dart_CObject* library_uri_message = message->value.as_array.values[3];
   ASSERT(library_uri_message != NULL);
-  Dart_CObject* payload_message = message->value.as_array.values[3];
+  Dart_CObject* payload_message = message->value.as_array.values[4];
   ASSERT(payload_message != NULL);
 
   // Grab the tag.
@@ -84,6 +86,10 @@ void Loader::IOResult::Setup(Dart_CObject* message) {
   ASSERT(uri_message->type == Dart_CObject_kString);
   uri = strdup(uri_message->value.as_string);
 
+  // Grab the resolved uri.
+  ASSERT(resolved_uri_message->type == Dart_CObject_kString);
+  resolved_uri = strdup(resolved_uri_message->value.as_string);
+
   // Grab the library uri if one is present.
   if (library_uri_message->type != Dart_CObject_kNull) {
     ASSERT(library_uri_message->type == Dart_CObject_kString);
@@ -113,6 +119,7 @@ void Loader::IOResult::Setup(Dart_CObject* message) {
 
 void Loader::IOResult::Cleanup() {
   free(uri);
+  free(resolved_uri);
   free(library_uri);
   free(payload);
 }
@@ -268,6 +275,8 @@ bool Loader::ProcessResultLocked(Loader* loader, Loader::IOResult* result) {
   // dropping the lock below |result| may no longer valid.
   Dart_Handle uri =
       Dart_NewStringFromCString(reinterpret_cast<char*>(result->uri));
+  Dart_Handle resolved_uri =
+      Dart_NewStringFromCString(reinterpret_cast<char*>(result->resolved_uri));
   Dart_Handle library_uri = Dart_Null();
   if (result->library_uri != NULL) {
     library_uri =
@@ -360,20 +369,20 @@ bool Loader::ProcessResultLocked(Loader* loader, Loader::IOResult* result) {
 
   switch (tag) {
     case Dart_kImportTag:
-      dart_result = Dart_LoadLibrary(uri, source, 0, 0);
+      dart_result = Dart_LoadLibrary(uri, resolved_uri, source, 0, 0);
     break;
     case Dart_kSourceTag: {
       ASSERT(library_uri != Dart_Null());
       Dart_Handle library = Dart_LookupLibrary(library_uri);
       ASSERT(!Dart_IsError(library));
-      dart_result = Dart_LoadSource(library, uri, source, 0, 0);
+      dart_result = Dart_LoadSource(library, uri, resolved_uri, source, 0, 0);
     }
     break;
     case Dart_kScriptTag:
       if (is_snapshot) {
         dart_result = Dart_LoadScriptFromSnapshot(payload, payload_length);
       } else {
-        dart_result = Dart_LoadScript(uri, source, 0, 0);
+        dart_result = Dart_LoadScript(uri, resolved_uri, source, 0, 0);
       }
     break;
     default:
@@ -653,7 +662,7 @@ Dart_Handle Loader::DartColonLibraryTagHandler(Dart_LibraryTag tag,
     Dart_Handle part_uri_obj = DartUtils::NewString(part_uri);
     free(part_uri);
     return Dart_LoadSource(library,
-                           part_uri_obj,
+                           part_uri_obj, Dart_Null(),
                            Builtin::PartSource(id, url_string), 0, 0);
   }
   // All cases should have been handled above.