Improve tools/run_dev.sh to allow custom flags

It is currently impossible or very hard to run tools/run_dev.sh
with a jvm debug port open.

With this change, one can simply run 'tools/run_dev.sh --debug' to open
 the default jvm debug port.

Change-Id: Ie3702affb3a7ee604cfa2dca6836135e0e8663b7

Documentation/developer-guide.md

diff --git a/Documentation/developer-guide.md b/Documentation/developer-guide.md
index 5b64e5e..d36a24d 100644
--- a/Documentation/developer-guide.md
+++ b/Documentation/developer-guide.md
@@ -70,6 +70,16 @@
 http://localhost:8080/ to view your local copy of gitiles, which
 will serve any repositories under `/path/to/repositories`.
 
+Passing `--debug` option to `tools/run_dev.sh` will suspend the runtime until a
+remote debugger connects to port 5005. If you don't want to suspend the
+runtime, make sure to assign value `n` to environment variable
+`DEFAULT_JVM_DEBUG_SUSPEND`:
+
+```
+cd /path/to/repositories  # Don't run from the gitiles repo.
+export DEFAULT_JVM_DEBUG_SUSPEND=n; /path/to/gitiles/tools/run_dev.sh --debug
+```
+
 To run unit tests, refer to the aforementioned bazel test command.
 
 ## Pushing your changes

tools/run_dev.sh

diff --git a/tools/run_dev.sh b/tools/run_dev.sh
index 497e9d3..1f4ed5e 100755
--- a/tools/run_dev.sh
+++ b/tools/run_dev.sh
@@ -18,9 +18,18 @@
 
 ROOT="$(cd $(dirname "$0")/..; pwd)"
 PROPERTIES=
-if [ "x$1" != "x" ]; then
-  PROPERTIES="--jvm_flag=-Dcom.google.gitiles.configPath=$1"
-fi
+
+NUMBER_OF_ARGUMENTS=$#
+while test $# -gt 0
+do
+    case "$1" in
+        --debug) PROPERTIES="$PROPERTIES --debug"
+            ;;
+        *) if [ $NUMBER_OF_ARGUMENTS -eq $# ]; then PROPERTIES="$PROPERTIES --jvm_flag=-Dcom.google.gitiles.configPath=$1"; fi
+            ;;
+    esac
+    shift
+done
 
 PROPERTIES="$PROPERTIES --jvm_flag=-Dcom.google.gitiles.sourcePath=$ROOT"
 
@@ -29,4 +38,5 @@
   bazel build java/com/google/gitiles/dev
 )
 
+set -x
 "$ROOT/bazel-bin/java/com/google/gitiles/dev/dev" $PROPERTIES