media: Bundle Widevine CDM on Win/Mac.

chrome/browser/component_updater/widevine_cdm_component_installer.cc

 // Copyright (c) 2013 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.
 
 #include "chrome/browser/component_updater/widevine_cdm_component_installer.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
 #include <string>
@@ skipping 329 matching lines @@
   const base::FilePath adapter_version_path =
       GetPlatformDirectory(cdm_install_dir).AppendASCII(kCdmAdapterVersionName);
   const base::FilePath adapter_install_path =
       GetPlatformDirectory(cdm_install_dir)
           .AppendASCII(kWidevineCdmAdapterFileName);
 
   VLOG(1) << "UpdateCdmAdapter: version" << cdm_version.GetString()
           << " adapter_install_path=" << adapter_install_path.AsUTF8Unsafe()
           << " adapter_version_path=" << adapter_version_path.AsUTF8Unsafe();
 
+  base::FilePath adapter_source_path;
+  PathService::Get(chrome::FILE_WIDEVINE_CDM_ADAPTER, &adapter_source_path);
+
   const std::string chrome_version = version_info::GetVersionNumber();
   DCHECK(!chrome_version.empty());
   std::string adapter_version;
-  if (!base::ReadFileToString(adapter_version_path, &adapter_version) ||
-      adapter_version != chrome_version ||
-      !base::PathExists(adapter_install_path)) {
+
+  if (adapter_install_path != adapter_source_path &&

[xhwang, 2016/05/20 19:30:00]

Being paranoid about this check... If there's an issue in this code (I don't
know how), we could end up overwritting the bundled adapter on line 369. Maybe
we should check that if the install path is within DIR_COMPONENT, don't copy,
just to be on the safer side?

[ddorwin, 2016/05/20 21:37:22]

You should have a comment to explain this. To isolate the condition, break it
up:

if (!=) 
  NOTREACHED() << Reason;
  return;
}

[xhwang, 2016/05/20 23:46:11]

Updated comments.

+      (!base::ReadFileToString(adapter_version_path, &adapter_version) ||
+       adapter_version != chrome_version ||
+       !base::PathExists(adapter_install_path))) {
     int bytes_written = base::WriteFile(
         adapter_version_path, chrome_version.data(), chrome_version.size());
     if (bytes_written < 0 ||
         static_cast<size_t>(bytes_written) != chrome_version.size()) {
       PLOG(WARNING) << "Failed to write Widevine CDM adapter version file.";
       // Ignore version file writing failure and try to copy the CDM adapter.
     }
 
-    base::FilePath adapter_source_path;
-    PathService::Get(chrome::FILE_WIDEVINE_CDM_ADAPTER, &adapter_source_path);
     if (!base::CopyFile(adapter_source_path, adapter_install_path)) {
       PLOG(WARNING) << "Failed to copy Widevine CDM adapter.";
       return;
     }
   }
 
   BrowserThread::PostTask(
       content::BrowserThread::UI, FROM_HERE,
       base::Bind(&RegisterWidevineCdmWithChrome, cdm_version, cdm_install_dir,
                  base::Passed(&manifest)));
@@ skipping 10 matching lines @@
   std::unique_ptr<ComponentInstallerTraits> traits(
       new WidevineCdmComponentInstallerTraits);
   // |cus| will take ownership of |installer| during installer->Register(cus).
   DefaultComponentInstaller* installer =
       new DefaultComponentInstaller(std::move(traits));
   installer->Register(cus, base::Closure());
 #endif  // defined(WIDEVINE_CDM_AVAILABLE) && defined(WIDEVINE_CDM_IS_COMPONENT)
 }
 
 }  // namespace component_updater