Not mask exception thrown by toString in String::UtfValue etc.

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 09125e1407c1ae84921005737437dc74f79ddf0d..1b240dc4e825942d9db2a72f4a50ca3cab962b1f 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -17478,4 +17478,37 @@ class ThreadInterruptTest {
 THREADED_TEST(SemaphoreInterruption) {
   ThreadInterruptTest().RunTest();
 }
+
+
+TEST(Utf8ValueException) {
+  v8::HandleScope scope;
+  LocalContext context;
+
+  Handle<Value> object = CompileRun(
+      "var obj = { toString : function() { throw 'deadbeef';  } }; obj");
+
+  { v8::TryCatch try_catch;
+    v8::String::Utf8Value utf8_value(object);
+    CHECK(try_catch.HasCaught());
+    CHECK_EQ("deadbeef", *v8::String::Utf8Value(try_catch.Exception()));
+  }
+
+  { v8::TryCatch try_catch;
+    v8::String::AsciiValue ascii_value(object);
+    CHECK(try_catch.HasCaught());
+    CHECK_EQ("deadbeef", *v8::String::Utf8Value(try_catch.Exception()));
+  }
+
+  { v8::TryCatch try_catch;
+    v8::String::Value value(object);
+    CHECK(try_catch.HasCaught());
+    CHECK_EQ("deadbeef", *v8::String::Utf8Value(try_catch.Exception()));
+  }
+
+  // It should work fine without any TryCatch.
+  v8::String::Utf8Value utf8_value(object);
+  v8::String::AsciiValue ascii_value(object);
+  v8::String::Value value(object);
+}
+
 #endif  // WIN32