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

runtime/bin/file.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/file.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 
 #include "include/dart_api.h"
@@ skipping 130 matching lines @@
   File* file = reinterpret_cast<File*>(value);
   if (file != NULL) {
     Dart_Handle buffer_obj = Dart_GetNativeArgument(args, 1);
     ASSERT(Dart_IsList(buffer_obj));
     int64_t offset =
         DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
     int64_t length =
         DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 3));
     intptr_t array_len = 0;
     Dart_Handle result = Dart_ListLength(buffer_obj, &array_len);
-    ASSERT(Dart_IsValid(result));
+    ASSERT(!Dart_IsError(result));
     ASSERT((offset + length) <= array_len);
     uint8_t* buffer = new uint8_t[length];
     int total_bytes_read =
         file->Read(reinterpret_cast<void*>(buffer), length);
     /*
      * Reading 0 indicates end of file.
      */
     if (total_bytes_read >= 0) {
       result =
           Dart_ListSetAsBytes(buffer_obj, offset, buffer, total_bytes_read);
-      ASSERT(Dart_IsValid(result));
+      ASSERT(!Dart_IsError(result));
       return_value = total_bytes_read;
     }
     delete[] buffer;
   }
   Dart_SetReturnValue(args, Dart_NewInteger(return_value));
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(File_WriteList)(Dart_NativeArguments args) {
   Dart_EnterScope();
   intptr_t return_value = -1;
   intptr_t value =
       DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 0));
   File* file = reinterpret_cast<File*>(value);
   if (file != NULL) {
     Dart_Handle buffer_obj = Dart_GetNativeArgument(args, 1);
     ASSERT(Dart_IsList(buffer_obj));
     int64_t offset =
         DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
     int64_t length =
         DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 3));
     intptr_t buffer_len = 0;
     Dart_Handle result = Dart_ListLength(buffer_obj, &buffer_len);
-    ASSERT(Dart_IsValid(result));
+    ASSERT(!Dart_IsError(result));
     ASSERT((offset + length) <= buffer_len);
     uint8_t* buffer = new uint8_t[length];
     result = Dart_ListGetAsBytes(buffer_obj, offset, buffer, length);
-    ASSERT(Dart_IsValid(result));
+    ASSERT(!Dart_IsError(result));
     int total_bytes_written =
         file->Write(reinterpret_cast<void*>(buffer), length);
     if (total_bytes_written >= 0) {
       return_value = total_bytes_written;
     }
     delete[] buffer;
   }
   Dart_SetReturnValue(args, Dart_NewInteger(return_value));
   Dart_ExitScope();
 }
@@ skipping 56 matching lines @@
   Dart_EnterScope();
   const char* str =
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 0));
   char* path = File::GetCanonicalPath(str);
   if (path != NULL) {
     Dart_SetReturnValue(args, Dart_NewString(path));
     free(path);
   }
   Dart_ExitScope();
 }