The symptom : when text is selected and the device is rotated,
sometimes the keyboard sets the word as being composed around
the start of the selection. Upon the next rotation this ends up
with the keyboard committing some text in place of the selection.

The cause : another bug in the framework with rotation >.>
The keyboard receives a call to startInput with a wrong cursor
position, namely one that does not represent a selection. The
keyboard sets a composition according to this wrong data. When
the keyboard is rotated again, it commits the text, which takes
the place of the selection.

The solution : actually when restarting input the keyboard
realizes that the cursor position is wrong. We cancel composition
at that time.
For robustness, this change also implements two other defensive
changes : upon call to onUpdateSelection, we actually realize
that the previous values were wrong, so we also fix it at that
time, and in addition, when rotating, we finishComposingText()
instead of commitText() which is less dangerous. Implementing
this later change also allows us to let less internal variables
from InputLogic escape to LatinIME, so it's also a good change
for design.

Bug: 14140799

Change-Id: Ib10de18e53e376ac1bbc8487e13d969828483346