Build warning, when compiling an opt b2g build for a device: { widget/gonk/ProcessOrientation.cpp: In member function 'int mozilla::ProcessOrientation::OnSensorChanged(const mozilla::hal::SensorData&, int)': widget/gonk/ProcessOrientation.cpp:210:8: warning: variable 'isAccelerating' set but not used [-Wunused-but-set-variable] bool isAccelerating = false; ^ widget/gonk/ProcessOrientation.cpp:211:8: warning: variable 'isFlat' set but not used [-Wunused-but-set-variable] bool isFlat = false; ^ widget/gonk/ProcessOrientation.cpp:212:8: warning: variable 'isSwinging' set but not used [-Wunused-but-set-variable] bool isSwinging = false; ^ } These bools are only used in a LOGD statement, which is currently #ifdeffed to be a no-op, like so: > 30 #if 0 > 31 #define LOGD(args...) __android_log_print(ANDROID_LOG_DEBUG, "ProcessOrientation" , ## args) > 32 #else > 33 #define LOGD(args...) > 34 #endif > 35 The best way to hack around the build warning is probably just "mozilla::unused", I think. (DebugOnly<> won't work, because these variables aren't even used in debug builds, unless you tweak that "#if 0" check.)

You can't quite see it in the patch-context, but I'm adding these "unused <<" statements right after this LOGD statement which actually references these variables: http://mxr.mozilla.org/mozilla-central/source/widget/gonk/ProcessOrientation.cpp?rev=ae78bb875714&mark=303-303,311-312#303

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=84e8629c4ce0