widevine: Support CDM host verification and storage ID (fixes issue #3404)

This functionality will be enabled if .sig files exist in the required
locations. See the issue for details.

libcef/common/util_mac.h

@@ -8,15 +8,16 @@
 
 #include <string>
 
-namespace base {
-class FilePath;
-}
+#include "base/files/file_path.h"
 
 namespace util_mac {
 
 // Returns the path to the NSLibraryDirectory (e.g. "~/Library").
 bool GetLocalLibraryDirectory(base::FilePath* result);
 
+// Returns the framework name (e.g. "Chromium Embedded Framework").
+base::FilePath::StringType GetFrameworkName();
+
 // Returns the path to the CEF framework directory inside the top-level app
 // bundle (e.g. "myapp.app/Contents/Frameworks/Chromium Embedded
 // Framework.framework"). May return an empty value if not running in an app