Fix undefined behavior (not returning a value from a function with return).

Bug: 17379740

This function was missing a return statement, even though it declares a return
type. This is undefined behavior, which clang miscompiled into just falling
through to a later function in some cases. Adding the return statement
fixes the undefined behavior (and probably fixes a bug too).

Change-Id: I05c03b6473b831769dc4fa8b5ba43fb4249f7626