This CL moves the code building index of IMEs from
InputMethodAndLanguageSettings to VirtualKeyboardFragment and
AvailableVirtualKeyboardFragment, so that a search landing page of IME
becomes one of the fragment correctly depending on the IME state.
Bug: 32643633
Test: Manually installing/uninstalling AOSP LatinIME.apk while
Settings app is/isn't running, then search AOSP and verify the
landing page is correctly determined by the IME's enable state.
Test: Update robolectric DynamicIndexableContentMonitorTest
Change-Id: Ie44f358c2d3919fc864f4f88e6229293113823dd
e776821a8d