Use FakeImeKeyboard when running in mash.

ui/base/ime/chromeos/ime_keyboard_ozone.h

Index: ui/base/ime/chromeos/ime_keyboard_ozone.h
diff --git a/ui/base/ime/chromeos/ime_keyboard_ozone.h b/ui/base/ime/chromeos/ime_keyboard_ozone.h
index d42791a2b98d6482810cd8c49fd6c6aeb129859e..29254682efa3395e93d48eb26ddc46ce87efad85 100644
--- a/ui/base/ime/chromeos/ime_keyboard_ozone.h
+++ b/ui/base/ime/chromeos/ime_keyboard_ozone.h
@@ -7,6 +7,7 @@
 
 #include "ui/base/ime/chromeos/ime_keyboard.h"
 
+#include <memory>
 #include <string>
 
 #include "base/compiler_specific.h"
@@ -22,7 +23,7 @@ namespace input_method {
 
 class UI_BASE_IME_EXPORT ImeKeyboardOzone : public ImeKeyboard {
  public:
-  ImeKeyboardOzone(ui::InputController* controller);
+  ImeKeyboardOzone();
   ~ImeKeyboardOzone() override;
 
   bool SetCurrentKeyboardLayoutByName(const std::string& layout_name) override;
@@ -36,6 +37,7 @@ class UI_BASE_IME_EXPORT ImeKeyboardOzone : public ImeKeyboard {
   bool CapsLockIsEnabled() override;
 
  private:
+  std::unique_ptr<ui::InputController> stub_controller_;
   ui::InputController* input_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(ImeKeyboardOzone);