Revert of Update Layer Hoisting to store its atlas texture in the resource cache

src/gpu/GrLayerCache.cpp

Index: src/gpu/GrLayerCache.cpp
diff --git a/src/gpu/GrLayerCache.cpp b/src/gpu/GrLayerCache.cpp
index 105ee04e53cd1a26f6ab78238211229bc3916225..9af89a34665664e42499623bab05e46cc60cd156 100644
--- a/src/gpu/GrLayerCache.cpp
+++ b/src/gpu/GrLayerCache.cpp
@@ -27,11 +27,9 @@
         SkASSERT(fRect.isEmpty());
         SkASSERT(nullptr == fPlot);
         SkASSERT(!fLocked);     // layers without a texture cannot be locked
-        SkASSERT(!fAtlased);    // can't be atlased if it doesn't have a texture
     }
 
     if (fPlot) {
-        SkASSERT(fAtlased);
         // If a layer has a plot (i.e., is atlased) then it must point to
         // the backing texture. Additionally, its rect should be non-empty.
         SkASSERT(fTexture && backingTexture == fTexture);
@@ -121,10 +119,8 @@
     }
     fLayerHash.rewind();
 
-    if (fAtlas) {
-        fAtlas->resetPlots();
-        fAtlas->detachBackingTexture();
-    }
+    // The atlas only lets go of its texture when the atlas is deleted.
+    fAtlas.free();
 }
 
 GrCachedLayer* GrLayerCache::createLayer(uint32_t pictureID,
@@ -171,7 +167,7 @@
 bool GrLayerCache::tryToAtlas(GrCachedLayer* layer,
                               const GrSurfaceDesc& desc,
                               bool* needsRendering) {
-    SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTextureOrNull() : nullptr, layer);)
+    SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTexture() : nullptr, layer);)
 
     SkASSERT(PlausiblyAtlasable(desc.fWidth, desc.fHeight));
     SkASSERT(0 == desc.fSampleCnt);
@@ -221,7 +217,7 @@
                 // The layer was successfully added to the atlas
                 const SkIRect bounds = SkIRect::MakeXYWH(loc.fX, loc.fY,
                                                          desc.fWidth, desc.fHeight);
-                layer->setTexture(fAtlas->getTexture(), bounds, true);
+                layer->setTexture(fAtlas->getTexture(), bounds);
                 layer->setPlot(plot);
                 layer->setLocked(true);
                 this->incPlotLock(layer->plot()->id());
@@ -231,7 +227,7 @@
 
             // The layer was rejected by the atlas (even though we know it is
             // plausibly atlas-able). See if a plot can be purged and try again.
-            if (!this->purgePlots(true)) {
+            if (!this->purgePlot()) {
                 break;  // We weren't able to purge any plots
             }
         }
@@ -264,14 +260,14 @@
         return false;
     }
 
-    layer->setTexture(tex, SkIRect::MakeWH(desc.fWidth, desc.fHeight), false);
+    layer->setTexture(tex, SkIRect::MakeWH(desc.fWidth, desc.fHeight));
     layer->setLocked(true);
     *needsRendering = true;
     return true;
 }
 
 void GrLayerCache::unlock(GrCachedLayer* layer) {
-    SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTextureOrNull() : nullptr, layer);)
+    SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTexture() : nullptr, layer);)
 
     if (nullptr == layer || !layer->locked()) {
         // invalid or not locked
@@ -303,11 +299,11 @@
         }
 
         layer->setPlot(nullptr);
-        layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
+        layer->setTexture(nullptr, SkIRect::MakeEmpty());
 #endif
 
     } else {
-        layer->setTexture(nullptr, SkIRect::MakeEmpty(), false);
+        layer->setTexture(nullptr, SkIRect::MakeEmpty());
     }
 
     layer->setLocked(false);
@@ -322,7 +318,7 @@
     for (; !iter.done(); ++iter) {
         const GrCachedLayer* layer = &(*iter);
 
-        layer->validate(fAtlas.get() ? fAtlas->getTextureOrNull() : nullptr);
+        layer->validate(fAtlas.get() ? fAtlas->getTexture() : nullptr);
 
         const GrPictureInfo* pictInfo = fPictureHash.find(layer->pictureID());
         if (!pictInfo) {
@@ -393,11 +389,10 @@
     }
 }
 
-bool GrLayerCache::purgePlots(bool justOne) {
+bool GrLayerCache::purgePlot() {
     SkDEBUGCODE(GrAutoValidateCache avc(this);)
     SkASSERT(fAtlas);
 
-    bool anyPurged = false;
     GrLayerAtlas::PlotIter iter;
     GrLayerAtlas::Plot* plot;
     for (plot = fAtlas->iterInit(&iter, GrLayerAtlas::kLRUFirst_IterOrder);
@@ -407,14 +402,11 @@
             continue;
         }
 
-        anyPurged = true;
         this->purgePlot(plot);
-        if (justOne) {
-            break;
-        }
-    }
-
-    return anyPurged;
+        return true;
+    }
+
+    return false;
 }
 
 void GrLayerCache::purgePlot(GrLayerAtlas::Plot* plot) {
@@ -463,56 +455,26 @@
         return;
     }
 
-    this->purgePlots(false); // clear them all out
+    GrLayerAtlas::PlotIter iter;
+    GrLayerAtlas::Plot* plot;
+    for (plot = fAtlas->iterInit(&iter, GrLayerAtlas::kLRUFirst_IterOrder);
+         plot;
+         plot = iter.prev()) {
+        SkASSERT(0 == fPlotLocks[plot->id()]);
+
+        this->purgePlot(plot);
+    }
 
     SkASSERT(0 == fPictureHash.count());
 
-    if (fAtlas->getTextureOrNull()) {
-        SkAutoTUnref<GrDrawContext> drawContext(
-                                    fContext->drawContext(fAtlas->getTexture()->asRenderTarget()));
-
-        if (drawContext) {
-            drawContext->discard();
-        }
-    }
-}
-#endif
-
-void GrLayerCache::begin() {
-    if (!fAtlas) {
-        return;
-    }
-
-    if (!fAtlas->reattachBackingTexture()) {
-        // We weren't able to re-attach. Clear out all the atlased layers.
-        this->purgePlots(false);
-        SkASSERT(0 == fPictureHash.count());
-    }
-#ifdef SK_DEBUG
-    else {
-        // we've reattached - everything had better make sense
-        SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
-        for (; !iter.done(); ++iter) {
-            GrCachedLayer* layer = &(*iter);
-
-            if (layer->isAtlased()) {
-                SkASSERT(fAtlas->getTexture() == layer->texture());
-            }
-        }
-    }
-#endif
-}
-
-void GrLayerCache::end() {
-    if (!fAtlas) {
-        return;
-    }
-
-    // Adding this call will clear out all the layers in the atlas
-    //this->purgePlots(false);
-
-    fAtlas->detachBackingTexture();
-}
+    SkAutoTUnref<GrDrawContext> drawContext(
+                                fContext->drawContext(fAtlas->getTexture()->asRenderTarget()));
+
+    if (drawContext) {
+        drawContext->discard();
+    }
+}
+#endif
 
 void GrLayerCache::processDeletedPictures() {
     SkTArray<SkPicture::DeletionMessage> deletedPictures;
@@ -527,7 +489,7 @@
 void GrLayerCache::writeLayersToDisk(const SkString& dirName) {
 
     if (fAtlas) {
-        GrTexture* atlasTexture = fAtlas->getTextureOrNull();
+        GrTexture* atlasTexture = fAtlas->getTexture();
         if (nullptr != atlasTexture) {
             SkString fileName(dirName);
             fileName.append("\\atlas.png");