To sort out the issue, main keyboard and mini keyboard have to share
the pointer trackers.

In order to prepare for that, KeyboardView needs to be refactored as
two separate classes. KeyboardView is responsible for drawing keyboard
visual. And LatinKeyboardBaseView is responsible for handling key
event and mini keyboard as well.

Bug: 4768084

Change-Id: I5643e333b9bdfde0c939a0693cea76bd22f38897

Bug: 4905427
Change-Id: I9b44d65e4503e46ce71322a3c325c55d188e34a0

This change also removes non-ASCII comment from strings.xml to
suppress resource compiler warning.

Change-Id: I96d3e8e2c7072816f32a15564745f8cdc3f91ee9

This change introduces:

* New KeyboardView attribute
  * keyLargeLetterRatio to specify large letter text size.
  * keyHintLabelRatio to specify hint label text size.
  * keyHintLabelColor to specify hint label text color.
  * keyPreviewTextRatio to specify key preview text size.
* New Key.keyLabelOption flags
  * alignLeftOfCenter, align the key label slightly left of the key center.
  * largeLetter, use keyLargeLetterRatio to draw key letter.
  * hasHintLabel, draw keyHintLabel at the right of key letter.
  * followKeyHintLabelRatio, draw the key label following keyHintLabelRatio size.
* Renames
  * Key.keyHintLetter to keyHintLabel.
  * Key.keylLabelOption fontFixedWidth to fontMonoSpace.
  * Key.keylLabelOption popupHint to hasPopupHint.
* Removes
  * number icon releted attributes and declarations.

Change-Id: I2f456737e3a46209e5f48b5155951b2b21a33859

bug: 4901934
Change-Id: I870ab2e621ef3640a84468f09c074cdd726dc963

Bug: 4903326
Change-Id: I2493d6dae613d2e37dfa8ce96b4cddc9a038160c

Change-Id: I7ed51fa4373fd5d1ebc6ebe52c6e93b27b43cff5

Bug: 4379983
Change-Id: I97f22e54827c6229054b514801401ffa5b4ed3b8