libwebm: added BlockEntry::GetKind op

Change-Id: I7d7daac0d3b8be1b8839f96503250170f675e34d

mkvparser.cpp

@@ -5145,11 +5145,18 @@ long Track::GetNext(
 }
 
 
-Track::EOSBlock::EOSBlock() : BlockEntry(NULL, LONG_MIN)
+Track::EOSBlock::EOSBlock() :
+    BlockEntry(NULL, LONG_MIN)
 {
 }
 
 
+BlockEntry::Kind Track::EOSBlock::GetKind() const
+{
+    return kBlockEOS;
+}
+
+
 const Block* Track::EOSBlock::GetBlock() const
 {
     return NULL;
@@ -7802,6 +7809,12 @@ SimpleBlock::SimpleBlock(
 }
 
 
+BlockEntry::Kind SimpleBlock::GetKind() const
+{
+    return kBlockSimple;
+}
+
+
 const Block* SimpleBlock::GetBlock() const
 {
     return &m_block;
@@ -7841,6 +7854,12 @@ void BlockGroup::ParseBlock(long long start, long long size)
 #endif
 
 
+BlockEntry::Kind BlockGroup::GetKind() const
+{
+    return kBlockGroup;
+}
+
+
 const Block* BlockGroup::GetBlock() const
 {
     return &m_block;