Deal with unhandled exceptions the same way in all Dart api functions.

runtime/bin/dartutils.cc

Index: runtime/bin/dartutils.cc
===================================================================
--- runtime/bin/dartutils.cc	(revision 1469)
+++ runtime/bin/dartutils.cc	(working copy)
@@ -13,14 +13,14 @@
   ASSERT(Dart_IsInteger(value_obj));
   int64_t value = 0;
   Dart_Handle result = Dart_IntegerValue(value_obj, &value);
-  ASSERT(Dart_IsValid(result));
+  ASSERT(!Dart_IsError(result));
   return value;
 }
 
 const char* DartUtils::GetStringValue(Dart_Handle str_obj) {
   const char* cstring = NULL;
   Dart_Handle result = Dart_StringToCString(str_obj, &cstring);
-  ASSERT(Dart_IsValid(result));
+  ASSERT(!Dart_IsError(result));
   return cstring;
 }
 
@@ -28,7 +28,7 @@
 bool DartUtils::GetBooleanValue(Dart_Handle bool_obj) {
   bool value = false;
   Dart_Handle result = Dart_BooleanValue(bool_obj, &value);
-  ASSERT(Dart_IsValid(result));
+  ASSERT(!Dart_IsError(result));
   return value;
 }
 
@@ -38,14 +38,14 @@
   Dart_Handle result = Dart_SetInstanceField(handle,
                                              Dart_NewString(name),
                                              Dart_NewInteger(val));
-  ASSERT(Dart_IsValid(result));
+  ASSERT(!Dart_IsError(result));
 }
 
 intptr_t DartUtils::GetIntegerInstanceField(Dart_Handle handle,
                                             const char* name) {
   Dart_Handle result =
       Dart_GetInstanceField(handle, Dart_NewString(name));
-  ASSERT(Dart_IsValid(result));
+  ASSERT(!Dart_IsError(result));
   intptr_t value = DartUtils::GetIntegerValue(result);
   return value;
 }
@@ -56,5 +56,5 @@
   Dart_Handle result = Dart_SetInstanceField(handle,
                                              Dart_NewString(name),
                                              Dart_NewString(val));
-  ASSERT(Dart_IsValid(result));
+  ASSERT(!Dart_IsError(result));
 }