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/resource_bundle_ctocpp.h

@@ -0,0 +1,42 @@
+// 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.
+//
+
+#ifndef CEF_LIBCEF_DLL_CTOCPP_RESOURCE_BUNDLE_CTOCPP_H_
+#define CEF_LIBCEF_DLL_CTOCPP_RESOURCE_BUNDLE_CTOCPP_H_
+#pragma once
+
+#ifndef USING_CEF_SHARED
+#pragma message("Warning: "__FILE__" may be accessed wrapper-side only")
+#else  // USING_CEF_SHARED
+
+#include "include/cef_resource_bundle.h"
+#include "include/capi/cef_resource_bundle_capi.h"
+#include "libcef_dll/ctocpp/ctocpp.h"
+
+// Wrap a C structure with a C++ class.
+// This class may be instantiated and accessed wrapper-side only.
+class CefResourceBundleCToCpp
+    : public CefCToCpp<CefResourceBundleCToCpp, CefResourceBundle,
+        cef_resource_bundle_t> {
+ public:
+  CefResourceBundleCToCpp();
+
+  // CefResourceBundle methods.
+  CefString GetLocalizedString(int string_id) OVERRIDE;
+  bool GetDataResource(int resource_id, void*& data,
+      size_t& data_size) OVERRIDE;
+  bool GetDataResourceForScale(int resource_id, ScaleFactor scale_factor,
+      void*& data, size_t& data_size) OVERRIDE;
+};
+
+#endif  // USING_CEF_SHARED
+#endif  // CEF_LIBCEF_DLL_CTOCPP_RESOURCE_BUNDLE_CTOCPP_H_