Add diamond-key remapping support.

chrome/browser/ui/ash/event_rewriter.cc

Index: chrome/browser/ui/ash/event_rewriter.cc
diff --git a/chrome/browser/ui/ash/event_rewriter.cc b/chrome/browser/ui/ash/event_rewriter.cc
index ad5fdec8222933b98b2b6ea4d600ac8061314596..63975c817c41fbd85fbc8599b0fdba2e535f6f0d 100644
--- a/chrome/browser/ui/ash/event_rewriter.cc
+++ b/chrome/browser/ui/ash/event_rewriter.cc
@@ -85,6 +85,7 @@ const struct ModifierFlagToPrefName {
   { Mod4Mask, 0, prefs::kLanguageRemapSearchKeyTo },
   { ControlMask, ui::EF_CONTROL_DOWN, prefs::kLanguageRemapControlKeyTo },
   { Mod1Mask, ui::EF_ALT_DOWN, prefs::kLanguageRemapAltKeyTo },
+  { Mod2Mask, 0, prefs::kLanguageRemapDiamondKeyTo },

[Yusuke Sato, 2013/01/23 07:12:18]

Please add unit tests. This class should be 100% tested.

[yoshiki, 2013/01/25 01:33:10]

Done.

 };
 
 // Gets a remapped key for |pref_name| key. For example, to find out which
@@ -467,6 +468,10 @@ bool EventRewriter::RewriteModifiers(ui::KeyEvent* event) {
   // First, remap |keysym|.
   const ModifierRemapping* remapped_key = NULL;
   switch (keysym) {
+    case XF86XK_Launch6:

[Yusuke Sato, 2013/01/23 07:12:18]

Add a similar comment to line 475-478.

[yoshiki, 2013/01/25 01:33:10]

Done.

+      remapped_key =

[Yusuke Sato, 2013/01/23 07:12:18]

Shouldn't we check the command line flag here? I think it would be safer to
always map XF86XK_Launch6 to Control on non-Stout devices where the new
configuration UI is not shown:

if (HasDiamondKey())
   ...
else
   ...

Please note that the pref you added is SYNCABLE_PREF.

[yoshiki, 2013/01/25 01:33:10]

Done.

+          GetRemappedKey(prefs::kLanguageRemapDiamondKeyTo, *pref_service);
+      break;
     // On Chrome OS, XF86XK_Launch7 (F16) with Mod3Mask is sent when Caps Lock
     // is pressed (with one exception: when IsMod3UsedByCurrentInputMethod() is
     // true, the key generates XK_ISO_Level3_Shift with Mod3Mask, not