Eliminate multiple benign overflow conditions.

In InputTransport.cpp, there are multiple loops in which loop
termination occurs when the value becomes zero. These termination
conditions are all written value-- > 0, which, since value is
unsigned, result in an unsigned integer overflow when value is 0.
These loops were refactored to eliminate these conditions.

Bug: 24171356
Change-Id: Ie135c4306d1f2cef2778e295242305ed5139221a