Improve the VSYNC api a bit.

- add the ability to set the vsync delivery rate, when the rate is
set to N>1 (ie: receive every N vsync), SF process' is woken up for
all of vsync, but clients only see the every N events.

- add the concept of one-shot vsync events, with a call-back
to request the next one. currently the call-back is a binder IPC.

Change-Id: I09f71df0b0ba0d88ed997645e2e2497d553c9a1b
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 58196d8..014c7e2 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -389,16 +389,10 @@
 // ----------------------------------------------------------------------------
 
 sp<IDisplayEventConnection> SurfaceFlinger::createDisplayEventConnection() {
-    sp<DisplayEventConnection> result(new DisplayEventConnection(this));
-    mEventThread->registerDisplayEventConnection(result);
+    sp<DisplayEventConnection> result(new DisplayEventConnection(mEventThread));
     return result;
 }
 
-void SurfaceFlinger::cleanupDisplayEventConnection(
-        const wp<DisplayEventConnection>& connection) {
-    mEventThread->unregisterDisplayEventConnection(connection);
-}
-
 // ----------------------------------------------------------------------------
 #if 0
 #pragma mark -