Switch to AVIO instead of a custom FFmpeg URLProtocol handler.

media/filters/in_memory_url_protocol.cc

Index: media/filters/in_memory_url_protocol.cc
diff --git a/media/filters/in_memory_url_protocol.cc b/media/filters/in_memory_url_protocol.cc
index cdff519e468fb21b63c0a252c6cf7c8cb6439257..c55438c7647be5ef0a440d3440d099af1421b01c 100644
--- a/media/filters/in_memory_url_protocol.cc
+++ b/media/filters/in_memory_url_protocol.cc
@@ -16,8 +16,8 @@ InMemoryUrlProtocol::InMemoryUrlProtocol(const uint8* data, int64 size,
 
 InMemoryUrlProtocol::~InMemoryUrlProtocol() {}
 
-size_t InMemoryUrlProtocol::Read(size_t size, uint8* data) {
-  size_t available_bytes = size_ - position_;
+int InMemoryUrlProtocol::Read(int size, uint8* data) {
+  int available_bytes = size_ - position_;
   if (size > available_bytes)
     size = available_bytes;