Update AccelerometerReader to support separate iio devices

chrome/browser/chromeos/display/display_preferences_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/display/display_preferences.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/content/display/screen_orientation_controller_chromeos.h"
@@ skipping 25 matching lines @@
 using ash::ResolutionNotificationController;
 
 namespace chromeos {
 namespace {
 const char kPrimaryIdKey[] = "primary-id";
 const char kMirroredKey[] = "mirrored";
 const char kPositionKey[] = "position";
 const char kOffsetKey[] = "offset";
 
 // The mean acceleration due to gravity on Earth in m/s^2.
-const float kMeanGravity = 9.80665f;
+const float kMeanGravity = -9.80665f;
 
 bool IsRotationLocked() {
   return ash::Shell::GetInstance()
       ->screen_orientation_controller()
       ->rotation_locked();
 }
 
 std::string ToPairString(const ash::DisplayIdPair& pair) {
   return base::Int64ToString(pair.first) + "," +
          base::Int64ToString(pair.second);
@@ skipping 916 matching lines @@
   // Sanity check. Restore to extended.
   StoreDisplayBoolPropertyForPair(pair, "default_unified", false);
   StoreDisplayBoolPropertyForPair(pair, "mirrored", false);
   LoadDisplayPreferences(false);
   UpdateDisplay("100x100,200x200");
   EXPECT_FALSE(display_manager->IsInMirrorMode());
   EXPECT_FALSE(display_manager->IsInUnifiedMode());
 }
 
 }  // namespace chromeos