Bug 978023 part.1 nsTextStateManager should be mozilla::IMEContentObserver and separated from nsIMEStateManager.cpp r=smaug

--HG--
rename : dom/events/nsIMEStateManager.cpp => dom/events/IMEContentObserver.cpp
rename : dom/events/nsIMEStateManager.cpp => dom/events/IMEContentObserver.h
Bug 978023 part.2 Clean up IMEContentObserver r=smaug
Bug 978023 part.3 Rename nsIMEStateManager to mozilla::IMEStateManager r=smaug

--HG--
rename : dom/events/nsIMEStateManager.cpp => dom/events/IMEStateManager.cpp
rename : dom/events/nsIMEStateManager.h => dom/events/IMEStateManager.h
Bug 978023 part.4 Clean up IMEStateManager r=smaug