a window could get stuck to gpu composition

this could happen after an orientation change. basically
we need to triger a geometry-changed when the very first buffer
is received

Change-Id: I097e411fd6612c18725737cffccdbf6b2af3511c

Author: pixelflinger

services/surfaceflinger/Layer.cpp

@@ -450,6 +450,12 @@ void Layer::lockPageFlip(bool& recomputeVisibleRegions)
         mActiveBuffer = mSurfaceTexture->getCurrentBuffer();
         mFrameLatencyNeeded = true;
 
+        if (oldActiveBuffer == NULL && mActiveBuffer != NULL) {
+            // the first time we receive a buffer, we need to trigger a
+            // geometry invalidation.
+            mFlinger->invalidateHwcGeometry();
+        }
+
         const Rect crop(mSurfaceTexture->getCurrentCrop());
         const uint32_t transform(mSurfaceTexture->getCurrentTransform());
         const uint32_t scalingMode(mSurfaceTexture->getCurrentScalingMode());