Revert "SurfaceFlinger: add a sysprop for GL backpressure"

This reverts commit 4658e11cbe1abae691454ddcf93a06763d1bf828.

Reason for revert: Seems to be responsible for breaking git_stage-aosp-master on aosp_arm64-eng, see b/140906153

Change-Id: I8968ca1bf95988b453bc33cd78a6389d6cb38a4f
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 6166789..2d31910 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -353,11 +353,6 @@
     mPropagateBackpressure = !atoi(value);
     ALOGI_IF(!mPropagateBackpressure, "Disabling backpressure propagation");
 
-    property_get("debug.sf.enable_gl_backpressure", value, "0");
-    mPropagateBackpressureClientComposition = atoi(value);
-    ALOGI_IF(mPropagateBackpressureClientComposition,
-             "Enabling backpressure propagation for Client Composition");
-
     property_get("debug.sf.enable_hwc_vds", value, "0");
     mUseHwcVirtualDisplays = atoi(value);
     ALOGI_IF(mUseHwcVirtualDisplays, "Enabling HWC virtual displays");
@@ -1675,9 +1670,9 @@
                 break;
             }
 
-            if (frameMissed && mPropagateBackpressure) {
-                if ((hwcFrameMissed && !gpuFrameMissed) ||
-                    mPropagateBackpressureClientComposition) {
+            // For now, only propagate backpressure when missing a hwc frame.
+            if (hwcFrameMissed && !gpuFrameMissed) {
+                if (mPropagateBackpressure) {
                     signalLayerUpdate();
                     break;
                 }