Add --keyboard-usability-test flag and always show keyboard unless manually hide

ui/keyboard/keyboard_switches.h

Index: ui/keyboard/keyboard_switches.h
diff --git a/ui/keyboard/keyboard_switches.h b/ui/keyboard/keyboard_switches.h
index a7d053314b61437ea37bb86529486ea81d485500..861f0ab5b095663f019b5a0c14340a5170d918c1 100644
--- a/ui/keyboard/keyboard_switches.h
+++ b/ui/keyboard/keyboard_switches.h
@@ -13,6 +13,9 @@ namespace switches {
 // Enables the virtual keyboard.
 KEYBOARD_EXPORT extern const char kEnableVirtualKeyboard[];
 
+// Enables the keyboard usability test.
+KEYBOARD_EXPORT extern const char kKeyboardUsabilityTest[];

[sadrul, 2013/10/23 14:01:49]

Shouldn't need to export (since it's not used outside of this component)

[bshe, 2013/10/23 17:08:43]

The reason I use EXPORT is this flag is expected to be used in ash just like
kEnableVirtualKeyboard. So I added the export here.  

On 2013/10/23 14:01:49, sadrul wrote:

[sadrul, 2013/10/23 17:45:06]

Where would you use this ash? This specific behaviour should be tested in
keyboard_unittest, and that test would add this flag to the CommandLine in the
test SetUp.

On 2013/10/23 17:08:43, bshe wrote:

[bshe, 2013/10/24 00:23:36]

It will be used to enable a special display mode(not implemented yet) in display
manager in ash. I will add a unit test here to make sure that keyboard always
show when flag is set.

On 2013/10/23 17:45:06, sadrul wrote:

+
 }  // namespace switches
 }  // namespace keyboard