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

utils.h

Index: utils.h
diff --git a/utils.h b/utils.h
index 776fc22b7b5439645da8d7c3caf82b52dcd08676..86ccfb71a7f0fa11b81c473021f114367471a749 100644
--- a/utils.h
+++ b/utils.h
@@ -29,6 +29,10 @@ bool IsOfficialBuild();
 // 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);