mac: Create a static mapping of accelerators in the main menu.

ui/events/keycodes/keyboard_code_conversion_mac.mm

Index: ui/events/keycodes/keyboard_code_conversion_mac.mm
diff --git a/ui/events/keycodes/keyboard_code_conversion_mac.mm b/ui/events/keycodes/keyboard_code_conversion_mac.mm
index fdda790be1fb10ca6f4c974a9a21c9a9046cdb49..e354e58883cbebb5bddf6e1a47da7a0b20e77869 100644
--- a/ui/events/keycodes/keyboard_code_conversion_mac.mm
+++ b/ui/events/keycodes/keyboard_code_conversion_mac.mm
@@ -521,18 +521,6 @@ int MacKeyCodeForWindowsKeyCode(KeyboardCode keycode,
     }
   }
 
-  // Control characters.

[erikchen, 2014/02/11 05:09:22]

This code is not used in the current code base (All calls to
MacKeyCodeForWindowsKeyCode use flags = 0). 

I don't understand lines 526-527, despite having looked at the CL in which this
code was introduced. https://codereview.chromium.org/2986004. This code causes
my newly written code to malfunction, so I removed it.

-  if (flags & NSControlKeyMask) {
-    if (keycode >= VKEY_A && keycode <= VKEY_Z)
-      *character = 1 + keycode - VKEY_A;
-    else if (macKeycode == kVK_ANSI_LeftBracket)
-      *character = 27;
-    else if (macKeycode == kVK_ANSI_Backslash)
-      *character = 28;
-    else if (macKeycode == kVK_ANSI_RightBracket)
-      *character = 29;
-  }
-
   // TODO(suzhe): Support characters for Option key bindings.
   return macKeycode;
 }