diff -r 000000000000 -r 6474c204b198 gfx/src/gfxCrashReporterUtils.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/src/gfxCrashReporterUtils.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef gfxCrashReporterUtils_h__
+#define gfxCrashReporterUtils_h__
+
+#include "gfxCore.h"
+
+namespace mozilla {
+
+/** \class ScopedGfxFeatureReporter
+  *
+  * On creation, adds "FeatureName?" to AppNotes
+  * On destruction, adds "FeatureName-", or "FeatureName+" if you called SetSuccessful().
+  *
+  * Any such string is added at most once to AppNotes, and is subsequently skipped.
+  *
+  * This ScopedGfxFeatureReporter class is designed to be fool-proof to use in functions that
+  * have many exit points. We don't want to encourage having function with many exit points.
+  * It just happens that our graphics features initialization functions are like that.
+  */
+class NS_GFX ScopedGfxFeatureReporter
+{
+public:
+  ScopedGfxFeatureReporter(const char *aFeature, bool force = false)
+    : mFeature(aFeature), mStatusChar('-')
+  {
+    WriteAppNote(force ? '!' : '?');
+  }
+  ~ScopedGfxFeatureReporter() {
+    WriteAppNote(mStatusChar);
+  }
+  void SetSuccessful() { mStatusChar = '+'; }
+
+  class AppNoteWritingRunnable;
+
+protected:
+  const char *mFeature;
+  char mStatusChar;
+
+private:
+  void WriteAppNote(char statusChar);
+};
+
+} // end namespace mozilla
+
+#endif // gfxCrashReporterUtils_h__