MacViews: Don't handle character events in textfield_unittest's MockInputMethod::DispatchKeyEvent.

ui/events/test/cocoa_test_event_utils.mm

Index: ui/events/test/cocoa_test_event_utils.mm
diff --git a/ui/events/test/cocoa_test_event_utils.mm b/ui/events/test/cocoa_test_event_utils.mm
index 9810d589419b6f6a1f2ebd1b6d01313e80cef5c5..5cd47568403b1d8e37da249f556228206d5e2ce6 100644
--- a/ui/events/test/cocoa_test_event_utils.mm
+++ b/ui/events/test/cocoa_test_event_utils.mm
@@ -203,6 +203,12 @@ NSEvent* SynthesizeKeyEvent(NSWindow* window,
   // logic to support it.
   flags &= ~NSAlphaShiftKeyMask;
 
+  // Call sites may generate unicode character events with an undefined
+  // keycode. Since it's not feasible to determine the correct keycode for
+  // each unicode character, we use a dummy keycode corresponding to key 'A'.

[tapted, 2016/06/29 07:21:39]

(also this probably only really matters for things with a NSCommandKeyMask since
|shifted_character| uses dom_key.ToCharacter() just below.)

[karandeepb, 2016/06/29 07:54:07]

I didn't get the bit about NSCommandKeyMask. This is needed for character events
with an undefined keycode. 

+  if (dom_key.IsCharacter() && keycode == ui::VKEY_UNKNOWN)
+    keycode = ui::VKEY_A;
+
   unichar character;
   unichar shifted_character;
   int macKeycode = ui::MacKeyCodeForWindowsKeyCode(