SampleApp: Make android_install_app and android_launch_app work consistently

platform_tools/android/bin/android_launch_app

Index: platform_tools/android/bin/android_launch_app
diff --git a/platform_tools/android/bin/android_launch_app b/platform_tools/android/bin/android_launch_app
index 1d4bc4695abdf94bc7731e7999696f98473db05f..e5fd54c96a411db63241820770bfc30f50d2161a 100755
--- a/platform_tools/android/bin/android_launch_app
+++ b/platform_tools/android/bin/android_launch_app
@@ -14,15 +14,17 @@ fi
 
 app=${APP_ARGS[0]}
 if [[ ${app} == '-'* ]]; then
+    echo "Defaulting to running SampleApp."
     app="SampleApp"
     APP_ARGS=( "SampleApp" ${APP_ARGS[*]} )
 fi
 
 if [[ ${app} == 'SampleApp' ]]; then
-    $ADB ${DEVICE_SERIAL} shell am start -S -n "com.skia.sampleapp/com.skia.SkiaSampleActivity" --es "cmdLineFlags" "${APP_ARGS[*]:1}"
+    activity="com.skia.sample_app/com.skia.SkiaSampleActivity"
 elif [[ ${app} == "VisualBench" ]] ; then
-    $ADB ${DEVICE_SERIAL} shell am start -S -n "com.skia.visualbench/com.skia.VisualBenchActivity" --es "cmdLineFlags" \"${APP_ARGS[*]:1}\"
+    activity="com.skia.visualbench/com.skia.VisualBenchActivity"
 else
     echo "ERROR: supports either 'SampleApp' or 'VisualBench' as valid apps"
+    exit 1
 fi
-
+$ADB ${DEVICE_SERIAL} shell "am start -S -n ${activity} --es cmdLineFlags \"${APP_ARGS[*]:1}\""