Replace "lower power mode" experiment

This replaces the previous low-power mode experiment, which
discarded refresh events, with a new experiment that alters
the refresh period.

(see also I2849e5ea335c0d2509fea1c315392bce7f20451d )

The feature is enabled by specifying a nonzero value for the
"refresh skip count", which indicates the number of periods
to skip.  For example, the command:

  adb shell service call SurfaceFlinger 1016 i32 1

sets a skip count of '1', yielding a 30Hz refresh rate on a device
with a 60Hz display.  Changing the last value to '2' would set the
refresh to 20Hz.  '0' returns to the default behavior.

Bug 15523257

Change-Id: I00039c22a55750e74035644c63800e4bee1c774a
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 3bdbb4f..f06db5c 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2682,11 +2682,8 @@
             // This is an experimental interface
             // Needs to be shifted to proper binder interface when we productize
             case 1016: {
-                mPrimaryDispSync.setLowPowerMode(true);
-                return NO_ERROR;
-            }
-            case 1017: {
-                mPrimaryDispSync.setLowPowerMode(false);
+                n = data.readInt32();
+                mPrimaryDispSync.setRefreshSkipCount(n);
                 return NO_ERROR;
             }
         }