Fix makefile parsing when chromium_org isn't checked out.

Some branches don't have external/chromium_org checked out but do
include frameworks/webview to get the null WebView implementation. Fix
the makefile so that it doesn't try to include the nonexistent in this case.

Change-Id: I573128973a92093da8ac0ce0c5cfa6df6af5255b
diff --git a/chromium/ b/chromium/
index eff3548..4902930 100644
--- a/chromium/
+++ b/chromium/
@@ -19,6 +19,13 @@
 LOCAL_PATH := $(call my-dir)
 CHROMIUM_PATH := external/chromium_org
+ifeq (,$(wildcard $(CHROMIUM_PATH)))
+# Some branches don't have the chromium sources; they shouldn't depend on
+# webview, but just in case this is a mistake, warn about it.
+$(warning Chromium sources missing, skipping webview package build)
+# Chromium sources exist, build the package.
 # Java glue layer JAR, calls directly into the chromium AwContents Java API.
 include $(CLEAR_VARS)
@@ -81,3 +88,5 @@
 $(LOCAL_BUILT_MODULE): $(jar_check_ok)
+endif  # CHROMIUM_PATH existence test