Removed HallEffect.

Change-Id: I677387d5c03a0e274b9ce5332bc56af367b19113
diff --git a/frc971/wpilib/BUILD b/frc971/wpilib/BUILD
index f9a7e9e..9417159 100644
--- a/frc971/wpilib/BUILD
+++ b/frc971/wpilib/BUILD
@@ -37,7 +37,6 @@
   deps = [
     '//aos/externals:wpilib',
     '//aos/common/logging',
-    ':hall_effect',
   ],
 )
 
@@ -141,13 +140,3 @@
     '//aos/common/logging:queue_logging',
   ],
 )
-
-cc_library(
-  name = 'hall_effect',
-  hdrs = [
-    'hall_effect.h',
-  ],
-  deps = [
-    '//aos/externals:wpilib',
-  ],
-)
diff --git a/frc971/wpilib/dma_edge_counting.h b/frc971/wpilib/dma_edge_counting.h
index 99ae80e..c145268 100644
--- a/frc971/wpilib/dma_edge_counting.h
+++ b/frc971/wpilib/dma_edge_counting.h
@@ -6,13 +6,12 @@
 
 #include "aos/common/macros.h"
 
-#include "frc971/wpilib/hall_effect.h"
-
 #include "DigitalInput.h"
 #include "Encoder.h"
 #include "AnalogInput.h"
 #include "Utility.h"
 #include "dma.h"
+#undef ERROR
 
 namespace frc971 {
 namespace wpilib {
diff --git a/frc971/wpilib/hall_effect.h b/frc971/wpilib/hall_effect.h
deleted file mode 100644
index d95b717..0000000
--- a/frc971/wpilib/hall_effect.h
+++ /dev/null
@@ -1,20 +0,0 @@
-#ifndef FRC971_WPILIB_HALL_EFFECT_H_
-#define FRC971_WPILIB_HALL_EFFECT_H_
-
-#include "DigitalInput.h"
-#undef ERROR
-
-namespace frc971 {
-namespace wpilib {
-
-// Inverts the output from a digital input.
-class HallEffect : public DigitalInput {
- public:
-  HallEffect(int index) : DigitalInput(index) {}
-  virtual bool Get() override { return !DigitalInput::Get(); }
-};
-
-}  // namespace wpilib
-}  // namespace frc971
-
-#endif  // FRC971_WPILIB_HALL_EFFECT_H_