Add Android copy_directory_contents_[to|from]_device scripts

platform_tools/android/bin/adb_pull_if_needed

Index: platform_tools/android/bin/adb_pull_if_needed
diff --git a/platform_tools/android/bin/adb_pull_if_needed b/platform_tools/android/bin/adb_pull_if_needed
new file mode 100755
index 0000000000000000000000000000000000000000..f4992b29c84e4011a501366ee665e5cb189fed55
--- /dev/null
+++ b/platform_tools/android/bin/adb_pull_if_needed
@@ -0,0 +1,10 @@
+#!/bin/bash
+#
+# Copy the contents of a directory from a device to the host.
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+source $SCRIPT_DIR/android_setup.sh
+source $SCRIPT_DIR/utils/setup_adb.sh
+
+adb_pull_if_needed ${APP_ARGS[@]}
+exit $?