AU: Include a bit flag (bit 31) in error codes to indicate non-normal boot mode.

BUG=chromium-os:10320
TEST=unit test, tested on device in normal and dev mode

Change-Id: I67d695bc167a4cc1a638711f047e2b86f8eaa8f1

Review URL: http://codereview.chromium.org/6098008
diff --git a/utils.h b/utils.h
index 776fc22..86ccfb7 100644
--- a/utils.h
+++ b/utils.h
@@ -29,6 +29,10 @@
 // otherwise.
 bool IsOOBEComplete();
 
+// Returns true if the boot mode is normal, false otherwise (e.g., developer or
+// recovery).
+bool IsNormalBootMode();
+
 // Writes the data passed to path. The file at path will be overwritten if it
 // exists. Returns true on success, false otherwise.
 bool WriteFile(const char* path, const char* data, int data_len);