Do not truncate message strings.

R=ishell@chromium.org
BUG=chromium:505539
LOG=N

Review URL: https://codereview.chromium.org/1214373005

Cr-Commit-Position: refs/heads/master@{#29481}

src/messages.cc

@@ -332,7 +332,6 @@ MaybeHandle<String> MessageTemplate::FormatMessage(int template_index,
                                                    Handle<String> arg0,
                                                    Handle<String> arg1,
                                                    Handle<String> arg2) {
-  static const int kMaxArgLength = 256;
   Isolate* isolate = arg0->GetIsolate();
   const char* template_string;
   switch (template_index) {
@@ -361,16 +360,7 @@ MaybeHandle<String> MessageTemplate::FormatMessage(int template_index,
       } else {
         DCHECK(i < arraysize(args));
         Handle<String> arg = args[i++];
-        int length = arg->length();
-        if (length > kMaxArgLength) {
-          builder.AppendString(
-              isolate->factory()->NewSubString(arg, 0, kMaxArgLength - 6));
-          builder.AppendCString("...");
-          builder.AppendString(
-              isolate->factory()->NewSubString(arg, length - 3, length));
-        } else {
-          builder.AppendString(arg);
-        }
+        builder.AppendString(arg);
       }
     } else {
       builder.AppendCharacter(*c);

test/cctest/test-api.cc

@@ -7553,6 +7553,22 @@ THREADED_TEST(ExceptionCreateMessage) {
 }
 
 
+THREADED_TEST(ExceptionCreateMessageLength) {
+  LocalContext context;
+  v8::HandleScope scope(context->GetIsolate());
+
+  // Test that the message is not truncated.
+  TryCatch try_catch(context->GetIsolate());
+  CompileRun(
+      "var message = 'm';"
+      "while (message.length < 1000) message += message;"
+      "throw message;");
+  CHECK(try_catch.HasCaught());
+
+  CHECK_LT(1000, try_catch.Message()->Get()->Length());
+}
+
+
 static void YGetter(Local<String> name,
                     const v8::PropertyCallbackInfo<v8::Value>& info) {
   ApiTestFuzzer::Fuzz();