Truncate very long javascript alert messages. They can overflow the UI and on Linux cause crashes.

chrome/browser/js_modal_dialog.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/js_modal_dialog.h"
 
+#include "base/string_util.h"
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/notification_type.h"
 #include "ipc/ipc_message.h"
 
+namespace {
+
+// The maximum sizes of various texts passed to us from javascript.
+const int kMessageTextMaxSize = 3000;
+const int kDefaultPromptTextSize = 2000;
+
+}  // namespace
+
 JavaScriptAppModalDialog::JavaScriptAppModalDialog(
     JavaScriptMessageBoxClient* client,
     const std::wstring& title,
     int dialog_flags,
     const std::wstring& message_text,
     const std::wstring& default_prompt_text,
     bool display_suppress_checkbox,
     bool is_before_unload_dialog,
     IPC::Message* reply_msg)
     : AppModalDialog(client->AsTabContents(), title),
       client_(client),
       extension_host_(client->AsExtensionHost()),
       dialog_flags_(dialog_flags),
       message_text_(message_text),
       default_prompt_text_(default_prompt_text),
       display_suppress_checkbox_(display_suppress_checkbox),
       is_before_unload_dialog_(is_before_unload_dialog),
       reply_msg_(reply_msg) {
+  // We trim the various parts of the message dialog because otherwise we can
+  // overflow the message dialog (and crash/hang the GTK+ version).
+  ElideString(message_text, kMessageTextMaxSize, &message_text_);
+  ElideString(default_prompt_text, kDefaultPromptTextSize,
+              &default_prompt_text_);
+
   DCHECK((tab_contents_ != NULL) != (extension_host_ != NULL));
   InitNotifications();
 }
 
 JavaScriptAppModalDialog::~JavaScriptAppModalDialog() {
 }
 
 void JavaScriptAppModalDialog::Observe(NotificationType type,
                                        const NotificationSource& source,
                                        const NotificationDetails& details) {
@@ skipping 76 matching lines @@
 #if !defined(OS_MACOSX)
     else if (extension_host_)
       extension_host_->OnMessageBoxClosed(reply_msg_, false, L"");
     else
       NOTREACHED();
 #endif
   }
   AppModalDialog::Cleanup();
 }