gitiles-dev: inject source path through a System property.

This makes gitiles-dev independent of the build system. It assumes
that nobody relies on .buckconfig being shipped into the gitiles jar.

Change-Id: Id3c5313061516aba835f0bc62160133913c7772e

tools/run_dev.sh

diff --git a/tools/run_dev.sh b/tools/run_dev.sh
index 14620d1..58493a6 100755
--- a/tools/run_dev.sh
+++ b/tools/run_dev.sh
@@ -16,12 +16,14 @@
 
 set -e
 
-ROOT="$(dirname "$0")/.."
+ROOT="$(cd $(dirname "$0")/..; pwd)"
 PROPERTIES=
 if [ "x$1" != "x" ]; then
   PROPERTIES="-Dcom.google.gitiles.configPath=$1"
 fi
 
+PROPERTIES="$PROPERTIES -Dcom.google.gitiles.sourcePath=$ROOT"
+
 (
   cd "$ROOT"
   buck build gitiles-dev:dev