Makes sure the keyboard typing isn't blocked when InputMethod::OnFocus() is not correctly called.

ui/base/ime/input_method_win.cc

Index: ui/base/ime/input_method_win.cc
diff --git a/ui/base/ime/input_method_win.cc b/ui/base/ime/input_method_win.cc
index 56bbac1b3244b1618eeaa89001155b815223cdf6..ea3a1806d20a11d78ca768203c5deb500c9b2197 100644
--- a/ui/base/ime/input_method_win.cc
+++ b/ui/base/ime/input_method_win.cc
@@ -262,6 +262,17 @@ LRESULT InputMethodWin::OnChar(HWND window_handle,
                                BOOL* handled) {
   *handled = TRUE;
 
+  if (!system_toplevel_window_focused()) {
+    LOG(ERROR) <<
+        "Char message got without the top-level window being activated.";

[yukawa, 2016/01/07 11:09:42]

(optional) We can also log |GetActiveWindow() == toplevel_window_handle_| as an
evidence that |system_toplevel_window_focused_| should have been true here.

[Shu Chen, 2016/01/08 02:04:11]

I think ::GetActiveWindow() could return non-top-level window. Right?

[yukawa, 2016/01/08 02:21:20]

(just FYI) AFAIK it always returns a top-level window, or NULL.  (We have
actually relied on that API in InputMethodWin::IsWindowFocused()).

[Shu Chen, 2016/01/08 09:00:16]

Done.

+    // There are random issues that the keyboard typing doesn't work.
+    // The root cause might be the InputMethod::OnFocus() is not correctly
+    // called when the top-level window is activated
+    // (in DNWA::HandleActivationChanged).
+    // Calls OnFocus here to unblock the keyboard typing.
+    OnFocus();
+  }
+
   // We need to send character events to the focused text input client event if
   // its text input type is ui::TEXT_INPUT_TYPE_NONE.
   if (GetTextInputClient()) {