Add plugin placeholder and policy support (issue #1708)

- Default plugin loading policy can be specified using the new
  `--plugin-policy=[allow|block|detect]` command-line flag.
- Move CefRequestHandler::OnBeforePluginLoad to
  CefRequestContextHandler and add a new policy argument that
  supports different actions (allow, block, detect, disable) on a
  per-plugin-instance basis.
- Add CefContextMenuHandler::RunContextMenu for providing a custom
  context menu implementation.
- Add CefResourceBundleHandler::GetDataResourceForScale for
  returning scaled resources (issue #1272).
- Add CefResourceBundle for retrieving resources from the resource
  bundle (*.pak) files loaded by CEF during startup or via the
  CefResourceBundleHandler.
- Linux: Fix Debug build IO access warning with CefGetMimeType.
- cef_unittests: Move the refcounting implementation from TestHandler
  to subclasses in order to support interface inheritance from
  subclasses.

libcef_dll/ctocpp/run_context_menu_callback_ctocpp.cc

@@ -0,0 +1,64 @@
+// Copyright (c) 2015 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+//
+// ---------------------------------------------------------------------------
+//
+// This file was generated by the CEF translator tool. If making changes by
+// hand only do so within the body of existing method and function
+// implementations. See the translator.README.txt file in the tools directory
+// for more information.
+//
+
+#include "libcef_dll/ctocpp/run_context_menu_callback_ctocpp.h"
+
+
+// VIRTUAL METHODS - Body may be edited by hand.
+
+void CefRunContextMenuCallbackCToCpp::Continue(int command_id,
+    EventFlags event_flags) {
+  cef_run_context_menu_callback_t* _struct = GetStruct();
+  if (CEF_MEMBER_MISSING(_struct, cont))
+    return;
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  // Execute
+  _struct->cont(_struct,
+      command_id,
+      event_flags);
+}
+
+void CefRunContextMenuCallbackCToCpp::Cancel() {
+  cef_run_context_menu_callback_t* _struct = GetStruct();
+  if (CEF_MEMBER_MISSING(_struct, cancel))
+    return;
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  // Execute
+  _struct->cancel(_struct);
+}
+
+
+// CONSTRUCTOR - Do not edit by hand.
+
+CefRunContextMenuCallbackCToCpp::CefRunContextMenuCallbackCToCpp() {
+}
+
+template<> cef_run_context_menu_callback_t* CefCToCpp<CefRunContextMenuCallbackCToCpp,
+    CefRunContextMenuCallback, cef_run_context_menu_callback_t>::UnwrapDerived(
+    CefWrapperType type, CefRunContextMenuCallback* c) {
+  NOTREACHED() << "Unexpected class type: " << type;
+  return NULL;
+}
+
+#ifndef NDEBUG
+template<> base::AtomicRefCount CefCToCpp<CefRunContextMenuCallbackCToCpp,
+    CefRunContextMenuCallback, cef_run_context_menu_callback_t>::DebugObjCt =
+    0;
+#endif
+
+template<> CefWrapperType CefCToCpp<CefRunContextMenuCallbackCToCpp,
+    CefRunContextMenuCallback, cef_run_context_menu_callback_t>::kWrapperType =
+    WT_RUN_CONTEXT_MENU_CALLBACK;