Revert of Add Ctrl+Alt+H as global shortcut to toggle high contrast mode.

ash/common/accelerators/accelerator_table.cc

Index: ash/common/accelerators/accelerator_table.cc
diff --git a/ash/common/accelerators/accelerator_table.cc b/ash/common/accelerators/accelerator_table.cc
index 1ee157e58c528a60b177273f1e7376ba12611208..8bc4a432c87fa81906654a7b841288f2ae990259 100644
--- a/ash/common/accelerators/accelerator_table.cc
+++ b/ash/common/accelerators/accelerator_table.cc
@@ -75,8 +75,9 @@
      TOUCH_HUD_CLEAR},
     {true, ui::VKEY_P, ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN,
      TOUCH_HUD_PROJECTION_TOGGLE},
-    {true, ui::VKEY_H, ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN,
-     TOGGLE_HIGH_CONTRAST},
+    // Accessibility: Spoken feedback shortcuts. The first one is to toggle
+    // spoken feedback on or off. The others are only valid when
+    // spoken feedback is enabled.
     {true, ui::VKEY_Z, ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN,
      TOGGLE_SPOKEN_FEEDBACK},
     {true, ui::VKEY_OEM_COMMA, ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN,
@@ -342,7 +343,6 @@
     KEYBOARD_BRIGHTNESS_DOWN,
     KEYBOARD_BRIGHTNESS_UP,
     TOGGLE_CAPS_LOCK,
-    TOGGLE_HIGH_CONTRAST,
     TOGGLE_SPOKEN_FEEDBACK,
     TOGGLE_MIRROR_MODE,
     TOGGLE_WIFI,
@@ -406,7 +406,6 @@
     SUSPEND,
     SWAP_PRIMARY_DISPLAY,
     TOGGLE_CAPS_LOCK,
-    TOGGLE_HIGH_CONTRAST,
     TOGGLE_MIRROR_MODE,
     TOGGLE_SPOKEN_FEEDBACK,
     TOGGLE_WIFI,
@@ -470,7 +469,6 @@
     POWER_RELEASED,
     SWAP_PRIMARY_DISPLAY,
     TOGGLE_CAPS_LOCK,
-    TOGGLE_HIGH_CONTRAST,
     TOGGLE_MIRROR_MODE,
     TOGGLE_SPOKEN_FEEDBACK,
     TOGGLE_WIFI,
@@ -533,7 +531,6 @@
     KEYBOARD_BRIGHTNESS_DOWN,
     KEYBOARD_BRIGHTNESS_UP,
     TOGGLE_CAPS_LOCK,
-    TOGGLE_HIGH_CONTRAST,
     TOGGLE_SPOKEN_FEEDBACK,
     TOGGLE_WIFI,
     VOLUME_DOWN,