Fix possible crash in keyboard::SendKeyEvent().

Bug: 750526
Change-Id: Id8a2dd90b835279e6dc39de493e174c563bf7493
Reviewed-on: https://chromium-review.googlesource.com/892682
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>
Reviewed-by: Blake O'Hare <blakeo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533190}

ui/keyboard/keyboard_util.cc

@@ -245,12 +245,14 @@ bool SendKeyEvent(const std::string type,
       if (!input_method)
         return false;
 
+      // This can be null if no text input field is not focused.
       ui::TextInputClient* tic = input_method->GetTextInputClient();
 
       SendProcessKeyEvent(ui::ET_KEY_PRESSED, host);
 
       ui::KeyEvent char_event(key_value, code, ui::EF_NONE);
-      tic->InsertChar(char_event);
+      if (tic)
+        tic->InsertChar(char_event);
       SendProcessKeyEvent(ui::ET_KEY_RELEASED, host);
     }
   } else {