gm: change ErrorBitfield to ErrorType/ErrorCombination

gm/gm_error.h

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * Error codes used by gmmain.cpp.
+ */
+
+namespace skiagm {
+
+    typedef int ErrorBitfield;

[epoger, 2013/03/21 17:56:27]

patchset 1: pull ErrorBitfield definitions into new gm_errors.h file.  No
behavioral changes.

+    // 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;
+
+}