Revert "revert surfaceflinger leak fix as it uncovered a crasher on xoom"

This reverts commit af6edba59e250adbdfa5b3c3be134f70d8c38a16.

Change-Id: I7793d3ca8a4d20a2b188364f47854328ab5f586d
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 33cb9a4..a7b5857 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -387,6 +387,9 @@
 {
     waitForEvent();
 
+    // call Layer's destructor
+    handleDestroyLayers();
+
     // check for transactions
     if (UNLIKELY(mConsoleSignals)) {
         handleConsoleEvents();
@@ -580,6 +583,31 @@
     commitTransaction();
 }
 
+void SurfaceFlinger::destroyLayer(LayerBase const* layer)
+{
+    Mutex::Autolock _l(mDestroyedLayerLock);
+    mDestroyedLayers.add(layer);
+    signalEvent();
+}
+
+void SurfaceFlinger::handleDestroyLayers()
+{
+    Vector<LayerBase const *> destroyedLayers;
+
+    { // scope for the lock
+        Mutex::Autolock _l(mDestroyedLayerLock);
+        destroyedLayers = mDestroyedLayers;
+        mDestroyedLayers.clear();
+    }
+
+    // call destructors without a lock held
+    const size_t count = destroyedLayers.size();
+    for (size_t i=0 ; i<count ; i++) {
+        //LOGD("destroying %s", destroyedLayers[i]->getName().string());
+        delete destroyedLayers[i];
+    }
+}
+
 sp<FreezeLock> SurfaceFlinger::getFreezeLock() const
 {
     return new FreezeLock(const_cast<SurfaceFlinger *>(this));