Tweaks to PPB_VarArrayBuffer in preperation for taking out of Dev.

webkit/plugins/ppapi/host_array_buffer_var.cc

Index: webkit/plugins/ppapi/host_array_buffer_var.cc
diff --git a/webkit/plugins/ppapi/host_array_buffer_var.cc b/webkit/plugins/ppapi/host_array_buffer_var.cc
index 248ff856235fb0de3c1bd0bc793986d191cbf2f4..e6612929b1e997ff7dd114ecf8e3ce9b849b78f5 100644
--- a/webkit/plugins/ppapi/host_array_buffer_var.cc
+++ b/webkit/plugins/ppapi/host_array_buffer_var.cc
@@ -25,6 +25,10 @@ void* HostArrayBufferVar::Map() {
   return buffer_.data();
 }
 
+void HostArrayBufferVar::Unmap() {
+  // We do not used shared memory on the host side. Nothing to do.
+}
+
 uint32 HostArrayBufferVar::ByteLength() {
   return buffer_.byteLength();
 }