gm: change ErrorBitfield to ErrorType/ErrorCombination

gm/gmmain.cpp

Index: gm/gmmain.cpp
===================================================================
--- gm/gmmain.cpp	(revision 8298)
+++ gm/gmmain.cpp	(working copy)
@@ -14,6 +14,7 @@
  */
 
 #include "gm.h"
+#include "gm_error.h"
 #include "gm_expectations.h"
 #include "system_preferences.h"
 #include "SkBitmap.h"
@@ -80,17 +81,6 @@
     #define CAN_IMAGE_PDF   0
 #endif
 
-typedef int ErrorBitfield;
-// an empty bitfield means no errors:
-const static ErrorBitfield kEmptyErrorBitfield                 = 0x00;
-// individual error types:
-const static ErrorBitfield kNoGpuContext_ErrorBitmask          = 0x01;
-const static ErrorBitfield kImageMismatch_ErrorBitmask         = 0x02;
-const static ErrorBitfield kMissingExpectations_ErrorBitmask   = 0x04;
-const static ErrorBitfield kWritingReferenceImage_ErrorBitmask = 0x08;
-// we typically ignore any errors matching this bitmask:
-const static ErrorBitfield kIgnorable_ErrorBitmask = kMissingExpectations_ErrorBitmask;
-
 using namespace skiagm;
 
 struct FailRec {