Add nanobench stats scripts to Skia repo.

bin/ac

+#!/bin/sh
+
+set -e
+
+BRANCH=$(git branch | grep \* | cut -d" "  -f 2)
+CLEAN=${CLEAN-clean}
+SAMPLES=100
+
+if [ $BRANCH == $CLEAN ]; then
+    echo "Comparing $BRANCH to itself."
+    exit 1
+fi
+
+git checkout $CLEAN
+./gyp_skia >/dev/null
+platform_tools/android/bin/android_ninja -t Release nanobench
+platform_tools/android/bin/android_run_skia -t Release nanobench $@ --skps /data/local/tmp/skps -i /data/local/tmp/resources --samples $SAMPLES -v > $CLEAN.log
+
+git checkout $BRANCH
+./gyp_skia >/dev/null
+platform_tools/android/bin/android_ninja -t Release nanobench
+platform_tools/android/bin/android_run_skia -t Release nanobench $@ --skps /data/local/tmp/skps -i /data/local/tmp/resources --samples $SAMPLES -v > $BRANCH.log
+
+compare $CLEAN.log $BRANCH.log