Prevent crash when flushing the layers cache

Bug #6258973

When flushing the layer caches we would attempt to delete the FBOs
associate with layers in the cache. The FBO property was however not
always properly cleared when recycling layers.

Change-Id: I7dedfe391d659a0849f1e1d84df17313b2c6e2b2

Author: Romain Guy

libs/hwui/LayerCache.cpp

@@ -69,10 +69,14 @@ void LayerCache::setMaxSize(uint32_t maxSize) {
 
 void LayerCache::deleteLayer(Layer* layer) {
     if (layer) {
-        LAYER_LOGD("Destroying layer %dx%d", layer->getWidth(), layer->getHeight());
+        GLuint fbo = layer->getFbo();
+        LAYER_LOGD("Destroying layer %dx%d, fbo %d", layer->getWidth(), layer->getHeight(), fbo);
+
         mSize -= layer->getWidth() * layer->getHeight() * 4;
-        layer->deleteFbo();
+
+        if (fbo) Caches::getInstance().fboCache.put(fbo);
         layer->deleteTexture();
+
         delete layer;
     }
 }
@@ -174,6 +178,10 @@ bool LayerCache::put(Layer* layer) {
                     victim->layer.getHeight());
         }
 
+        layer->deferredUpdateScheduled = false;
+        layer->renderer = NULL;
+        layer->displayList = NULL;
+
         LayerEntry entry(layer);
 
         mCache.add(entry);

libs/hwui/LayerRenderer.cpp

@@ -309,6 +309,7 @@ void LayerRenderer::destroyLayer(Layer* layer) {
         if (fbo) {
             flushLayer(layer);
             Caches::getInstance().fboCache.put(fbo);
+            layer->setFbo(0);
         }
 
         if (!Caches::getInstance().layerCache.put(layer)) {

libs/hwui/OpenGLRenderer.cpp

@@ -641,6 +641,7 @@ void OpenGLRenderer::composeLayer(sp<Snapshot> current, sp<Snapshot> previous) {
 
         // Put the FBO name back in the cache, if it doesn't fit, it will be destroyed
         mCaches.fboCache.put(current->fbo);
+        layer->setFbo(0);
     }
 
     dirtyClip();