libwebm: update to libwebm-1.0.0.28-28-gee0bab5

https://chromium.googlesource.com/webm/libwebm/+log/206d268d4d8066e5a37c49025325b80c95c771dd..ee0bab576c338c9807249b99588e352b7268cb62

only one commit affects this snapshot:
ee0bab5 Revert "mkvmuxer,Cluster::Size: make uint64 conversion explicit"

Bug: aomedia:3223
Change-Id: Ib1f21fc5589098af346d110ff88c94bb1ba0a027
(cherry picked from commit dc7efaa56c345d04c302bf85084ff8aa729f5b50)

third_party/libwebm/README.libaom

diff --git a/third_party/libwebm/README.libaom b/third_party/libwebm/README.libaom
index 5cc0a83..325604c 100644
--- a/third_party/libwebm/README.libaom
+++ b/third_party/libwebm/README.libaom
@@ -1,5 +1,5 @@
 URL: https://chromium.googlesource.com/webm/libwebm
-Version: 206d268d4d8066e5a37c49025325b80c95c771dd
+Version: ee0bab576c338c9807249b99588e352b7268cb62
 License: BSD
 License File: LICENSE.txt
 

third_party/libwebm/mkvmuxer/mkvmuxer.cc

diff --git a/third_party/libwebm/mkvmuxer/mkvmuxer.cc b/third_party/libwebm/mkvmuxer/mkvmuxer.cc
index 24c2888..ae36531 100644
--- a/third_party/libwebm/mkvmuxer/mkvmuxer.cc
+++ b/third_party/libwebm/mkvmuxer/mkvmuxer.cc
@@ -2622,8 +2622,7 @@
 
 uint64_t Cluster::Size() const {
   const uint64_t element_size =
-      EbmlMasterElementSize(static_cast<uint64_t>(libwebm::kMkvCluster),
-                            uint64_t{0xFFFFFFFFFFFFFFFFU}) +
+      EbmlMasterElementSize(libwebm::kMkvCluster, 0xFFFFFFFFFFFFFFFFULL) +
       payload_size_;
   return element_size;
 }