ime-service: Delete InputEngine.ProcessText.

It is deprecated and no longer used.

Bug: 1009903
Change-Id: I6774a4506bd0bb41a5d1a5909a40a2a781564b16
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833029
Auto-Submit: Darren Shen <shend@chromium.org>
Reviewed-by: Chris Palmer <palmer@chromium.org>
Reviewed-by: Keith Lee <keithlee@chromium.org>
Reviewed-by: Shu Chen <shuchen@chromium.org>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705445}
InputEngineContext::InputEngineContext(const std::string& ime) : ime_spec(ime) {
  std::string id = GetIdFromImeSpec(ime_spec);
  if (rulebased::Engine::IsImeSupported(id)) {
    engine = std::make_unique<rulebased::Engine>();
    engine->Activate(id);
  }
}

InputEngineContext::InputEngineContext(const std::string& ime) : ime_spec(ime) {
  std::string id = GetIdFromImeSpec(ime_spec);
  if (rulebased::Engine::IsImeSupported(id)) {
    engine = std::make_unique<rulebased::Engine>();
    engine->Activate(id);
  }
}
