Remove unused pre-commit hooks code
Remove unused pre-commit hooks code

This patch removes unused methods and properties of the AffectedFile and
InputAPI classes in hooks/pre_commit.py.

Eventually, the two classes will be replaced by their depot_tools
counterparts (see
https://www.chromium.org/developers/how-tos/depottools/presubmit-scripts).

BUG=#932
R=nduca@chromium.org

Review URL: https://codereview.appspot.com/238400043

vmpstr/trace-viewer,zeptonaut/catapult,catapult-project/catapult-csm,sahiljain/catapult,catapult-project/catapult,danbeam/catapult,catapult-project/catapult,SummerLW/Perf-Insight-Report,scottmcmaster/catapult,modulexcite/catapult,benschmaus/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,dstockwell/catapult,catapult-project/catapult,zeptonaut/catapult,SummerLW/Perf-Insight-Report,dstockwell/catapult,zeptonaut/catapult,catapult-project/catapult-csm,0x90sled/catapult,benschmaus/catapult,catapult-project/catapult,modulexcite/catapult,vmpstr/trace-viewer,dstockwell/catapult,vmpstr/trace-viewer,catapult-project/catapult-csm,0x90sled/catapult,benschmaus/catapult,sahiljain/catapult,benschmaus/catapult,0x90sled/catapult,danbeam/catapult,scottmcmaster/catapult,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,catapult-project/catapult,sahiljain/catapult,catapult-project/catapult,sahiljain/catapult,benschmaus/catapult,danbeam/catapult,catapult-project/catapult,sahiljain/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,danbeam/catapult,modulexcite/catapult,sahiljain/catapult,catapult-project/catapult-csm,dstockwell/catapult,catapult-project/catapult-csm,benschmaus/catapult,scottmcmaster/catapult,SummerLW/Perf-Insight-Report