Narrow down to one generic error per action.

action_processor.h

Index: action_processor.h
diff --git a/action_processor.h b/action_processor.h
index 7b1a312d4be841a073b259c61b2050e83513243a..96e16f05f6b20155368c000477c724c1c4162474 100644
--- a/action_processor.h
+++ b/action_processor.h
@@ -25,10 +25,15 @@ namespace chromeos_update_engine {
 enum ActionExitCode {
   kActionCodeSuccess = 0,
   kActionCodeError = 1,
-  kActionCodeInstallDeviceOpenError = 2,
-  kActionCodeKernelDeviceOpenError = 3,
-  kActionCodeDownloadTransferError = 4,
-  kActionCodeDownloadHashMismatchError = 5,
+  kActionCodeOmahaRequestError = 2,
+  kActionCodeOmahaResponseHandlerError = 3,
+  kActionCodeFilesystemCopierError = 4,
+  kActionCodePostinstallRunnerError = 5,
+  kActionCodeSetBootableFlagError = 6,
+  kActionCodeInstallDeviceOpenError = 7,
+  kActionCodeKernelDeviceOpenError = 8,
+  kActionCodeDownloadTransferError = 9,
+  kActionCodeDownloadHashMismatchError = 10,
 };
 
 class AbstractAction;