Fix two uninitialized variables in media

media/formats/mp4/box_definitions.cc

 // Copyright 2014 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/formats/mp4/box_definitions.h"
 
 #include "base/logging.h"
 #include "media/formats/mp4/es_descriptor.h"
 #include "media/formats/mp4/rcheck.h"
 
@@ skipping 743 matching lines @@
   bool sample_size_present = (flags & 0x200) != 0;
   bool sample_flags_present = (flags & 0x400) != 0;
   bool sample_composition_time_offsets_present = (flags & 0x800) != 0;
 
   if (data_offset_present) {
     RCHECK(reader->Read4(&data_offset));
   } else {
     data_offset = 0;
   }
 
-  uint32 first_sample_flags;
+  uint32 first_sample_flags = 0;
   if (first_sample_flags_present)
     RCHECK(reader->Read4(&first_sample_flags));
 
   int fields = sample_duration_present + sample_size_present +
       sample_flags_present + sample_composition_time_offsets_present;
   RCHECK(reader->HasBytes(fields * sample_count));
 
   if (sample_duration_present)
     sample_durations.resize(sample_count);
   if (sample_size_present)
@@ skipping 175 matching lines @@
 SampleDependsOn IndependentAndDisposableSamples::sample_depends_on(
     size_t i) const {
   if (i >= sample_depends_on_.size())
     return kSampleDependsOnUnknown;
 
   return sample_depends_on_[i];
 }
 
 }  // namespace mp4
 }  // namespace media