Add offset support to BitstreamBuffer.

content/common/gpu/media_messages.cc

Index: content/common/gpu/media_messages.cc
diff --git a/content/common/gpu/media_messages.cc b/content/common/gpu/media_messages.cc
index 74bd702850ad978d692deaa4ee6a5d2f256dc566..9db4ae17fb5e01ed62f40d0fe457249d595d544c 100644
--- a/content/common/gpu/media_messages.cc
+++ b/content/common/gpu/media_messages.cc
@@ -16,6 +16,8 @@ void ParamTraits<media::BitstreamBuffer>::Write(base::Pickle* m,
                                                 const param_type& p) {
   WriteParam(m, p.id());
   WriteParam(m, static_cast<uint64_t>(p.size()));
+  DCHECK_GE(p.offset(), 0);
+  WriteParam(m, static_cast<int64_t>(p.offset()));

[dcheng, 2016/03/05 01:30:57]

static_cast<uint64_t> (and corresponding change on the other side)

   WriteParam(m, p.presentation_timestamp());
   WriteParam(m, p.key_id());
   if (!p.key_id().empty()) {
@@ -30,7 +32,9 @@ bool ParamTraits<media::BitstreamBuffer>::Read(const base::Pickle* m,
                                                param_type* r) {
   DCHECK(r);
   uint64_t size = 0;
+  int64_t offset = 0;
   if (!(ReadParam(m, iter, &r->id_) && ReadParam(m, iter, &size) &&
+        ReadParam(m, iter, &offset) &&
         ReadParam(m, iter, &r->presentation_timestamp_) &&
         ReadParam(m, iter, &r->key_id_)))
     return false;
@@ -42,6 +46,13 @@ bool ParamTraits<media::BitstreamBuffer>::Read(const base::Pickle* m,
   }
   r->size_ = checked_size.ValueOrDie();
 
+  base::CheckedNumeric<off_t> checked_offset(offset);
+  if (!checked_offset.IsValid() || offset < 0) {
+    DLOG(ERROR) << "Invalid offset: " << offset;
+    return false;
+  }
+  r->offset_ = checked_offset.ValueOrDie();
+
   if (!r->key_id_.empty()) {
     if (!(ReadParam(m, iter, &r->iv_) && ReadParam(m, iter, &r->subsamples_)))
       return false;