Bug 940851 - Initialize acquire & release-fence fds of HWC_BACKGROUND layer. r=dwilson

widget/gonk/HwcComposer2D.cpp

@@ -525,6 +525,8 @@ HwcComposer2D::Render(EGLDisplay dpy, EGLSurface sur)
         mList->hwLayers[0].compositionType = HWC_BACKGROUND;
         mList->hwLayers[0].flags = HWC_SKIP_LAYER;
         mList->hwLayers[0].backgroundColor = {0};
+        mList->hwLayers[0].acquireFenceFd = -1;
+        mList->hwLayers[0].releaseFenceFd = -1;
         mList->hwLayers[0].displayFrame = {0, 0, mScreenRect.width, mScreenRect.height};
         Prepare(fbsurface->lastHandle, fbsurface->lastFenceFD);
     }

widget/gonk/libdisplay/GonkDisplayJB.cpp

@@ -234,6 +234,8 @@ GonkDisplayJB::Post(buffer_handle_t buf, int fence)
     /* Skip this layer so the hwc module doesn't complain about null handles */
     mList->hwLayers[0].flags = HWC_SKIP_LAYER;
     mList->hwLayers[0].backgroundColor = {0};
+    mList->hwLayers[0].acquireFenceFd = -1;
+    mList->hwLayers[0].releaseFenceFd = -1;
     /* hwc module checks displayFrame even though it shouldn't */
     mList->hwLayers[0].displayFrame = r;
     mList->hwLayers[1].compositionType = HWC_FRAMEBUFFER_TARGET;