macOS: Load the CEF framework using dlopen instead of direct linking (issue #2459)

This is a prerequisite for using the Chromium V2 sandbox.

include/wrapper/cef_library_loader.h

@@ -0,0 +1,116 @@
+// Copyright (c) 2018 Marshall A. Greenblatt. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the name Chromium Embedded
+// Framework nor the names of its contributors may be used to endorse
+// or promote products derived from this software without specific prior
+// written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CEF_INCLUDE_WRAPPER_CEF_LIBRARY_LOADER_H_
+#define CEF_INCLUDE_WRAPPER_CEF_LIBRARY_LOADER_H_
+#pragma once
+
+#include "include/base/cef_build.h"
+
+#ifdef __cplusplus
+#include <string>
+
+#include "include/base/cef_macros.h"
+
+extern "C" {
+#endif  // __cplusplus
+
+///
+// Load the CEF library at the specified |path|. Returns true (1) on
+// success and false (0) on failure.
+///
+int cef_load_library(const char* path);
+
+///
+// Unload the CEF library that was previously loaded. Returns true (1)
+// on success and false (0) on failure.
+///
+int cef_unload_library();
+
+#ifdef __cplusplus
+}
+
+#if defined(OS_MACOSX)
+
+///
+// Scoped helper for loading and unloading the CEF framework library at
+// runtime from the expected location in the app bundle. Loading at runtime
+// instead of linking directly is a requirement of the macOS sandbox
+// implementation.
+//
+// Example usage in the main process:
+//
+//   int main(int argc, char* argv[]) {
+//     CefScopedLibraryLoader library_loader;
+//     if (!library_loader.LoadInMain())
+//       return 1;
+//
+//     // Rest of the function here...
+//   }
+//
+// Example usage in the helper process:
+//
+//   int main(int argc, char* argv[]) {
+//     CefScopedLibraryLoader library_loader;
+//     if (!library_loader.LoadInHelper())
+//       return 1;
+//
+//     // Rest of the function here...
+//   }
+///
+class CefScopedLibraryLoader {
+ public:
+  CefScopedLibraryLoader();
+  ~CefScopedLibraryLoader();
+
+  ///
+  // Load the CEF framework in the main process from the expected app
+  // bundle location relative to the executable. Returns true if the
+  // load succeeds.
+  ///
+  bool LoadInMain() { return Load(false); }
+
+  ///
+  // Load the CEF framework in the helper process from the expected app
+  // bundle location relative to the executable. Returns true if the
+  // load succeeds.
+  ///
+  bool LoadInHelper() { return Load(true); }
+
+ private:
+  bool Load(bool helper);
+
+  bool loaded_;
+  DISALLOW_COPY_AND_ASSIGN(CefScopedLibraryLoader);
+};
+
+#endif  // defined(OS_MACOSX)
+#endif  // __cplusplus
+
+#endif  // CEF_INCLUDE_WRAPPER_CEF_LIBRARY_LOADER_H_