Use 'pssh' data to determine key_id properly

media/cdm/cenc_utils.cc

 // Copyright 2015 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 "media/cdm/cenc_utils.h"
 
 #include "base/stl_util.h"
 #include "media/formats/mp4/box_definitions.h"
 #include "media/formats/mp4/box_reader.h"
 
@@ skipping 71 matching lines @@
       return false;
 
     // Check all children for an appropriate 'pssh' box, concatenating any
     // key IDs found.
     for (const auto& child : children) {
       if (child.system_id == common_system_id && child.key_ids.size() > 0)
         result.insert(result.end(), child.key_ids.begin(), child.key_ids.end());
     }
   }
 
-  // No matching 'pssh' box found.
-  // TODO(jrummell): This should return true only if there was at least one
-  // key ID present. However, numerous test files don't contain the 'pssh' box
-  // for Common Format, so no keys are found. http://crbug.com/460308
   key_ids->swap(result);
-  return true;
+  return key_ids->size() > 0;
 }
 
 bool GetPsshData(const std::vector<uint8_t>& input,
                  const std::vector<uint8_t>& system_id,
                  std::vector<uint8_t>* pssh_data) {
   if (input.empty())
     return false;
 
   std::vector<mp4::FullProtectionSystemSpecificHeader> children;
   if (!ReadAllPsshBoxes(input, &children))
     return false;
 
   // Check all children for an appropriate 'pssh' box, returning |data| from
   // the first one found.
   for (const auto& child : children) {
     if (child.system_id == system_id) {
       pssh_data->assign(child.data.begin(), child.data.end());
       return true;
     }
   }
 
   // No matching 'pssh' box found.
   return false;
 }
 
 }  // namespace media