Update host verification API

content_decryption_module_ext.h

 // Copyright 2017 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.
 
 #ifndef CDM_CONTENT_DECRYPTION_MODULE_EXT_H_
 #define CDM_CONTENT_DECRYPTION_MODULE_EXT_H_
 
 #if defined(WIN32)
 #include <windows.h>
 #endif
@@ skipping 31 matching lines @@
   PlatformFile file = kInvalidPlatformFile;
 
   // Signature file for |file|.
   PlatformFile sig_file = kInvalidPlatformFile;
 };
 
 }  // namespace cdm
 
 extern "C" {
 
-// Verifies CDM host files, which are opened in read-only mode and passed in
-// |host_files|. The CDM MUST return as soon as possible and process the files
+// Functions in this file are dynamically retrieved by their versioned fucntion

[jrummell, 2017/01/19 18:44:19]

s/fucntion/function/ (last word on line).

[xhwang, 2017/01/19 19:42:18]

Done.

+// name. Increment the version number for any backward incompatible API changes.
+
+// Verifies CDM host. All files in |host_files| are opened in read-only mode.
+//
+// Returns false and close all files if verification failed immediately.
+// Otherwise the CDM MUST return true as soon as possible and process the files
 // asynchronously. All files MUST be closed by the CDM after this one-time
 // processing is finished.
-CDM_API void VerifyHostFiles(const cdm::HostFile* host_files,
-                             uint32_t num_files);
+CDM_API bool VerifyHost_0(const cdm::HostFile* host_files, uint32_t num_files);

[jrummell, 2017/01/19 18:44:19]

Should we also have the typedef for the calling signature here? I noticed in
your chrome change it simply referred to this file, but I wondered if it would
be better to have the typedef here. (And possibly the function name, although I
think #define VerifyHostFunctionName VerifyHost_0 is discouraged.)

[xhwang, 2017/01/19 19:42:18]

Summary of offline discussion.

Typically we don't do them in the header file to keep the interface clean. Also
looking at all examples in Chromium and we don't normally do this. So I'll keep
this as is for now. We can revisit this topic later.

 }
 
 #endif  // CDM_CONTENT_DECRYPTION_MODULE_EXT_H_