Revert of Fix bug in plot locking system (patchset #3 id:80001 of https://codereview.chromium.org/640323002/)

Reason for revert:
Failing unit tests

Original issue's description:
> Fix bug in plot locking system
>
> In the new MultiPictureDraw tests a single hoisted layer is reused multiple times. The previous plot locking scheme allowed GrCachedLayer objects to be aggressively deleted prematurely leaving the reusing GrHoistedLayer objects with dangling pointers.
>
> This CL changes the plot locking system to add a pseudo-ref for each GrHoistedLayer.
>
> NOTRY=true
>
> Committed: https://skia.googlesource.com/skia/+/5c481666c9678f43e039ad605457be3854cf8de3

TBR=jvanverth@google.com
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/643673004

1 files changed, 17 insertions, 7 deletions

diff --git a/src/gpu/GrLayerCache.cpp b/src/gpu/GrLayerCache.cpp
index 50f7abe830..0481d144e5 100644
--- a/src/gpu/GrLayerCache.cpp
+++ b/src/gpu/GrLayerCache.cpp
@@ -153,12 +153,14 @@ bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool do
 
     if (layer->locked()) {
         // This layer is already locked
+#ifdef SK_DEBUG
         if (layer->isAtlased()) {
-            this->incPlotLock(layer->plot()->id());
+            // It claims to be atlased
             SkASSERT(!dontAtlas);
             SkASSERT(layer->rect().width() == desc.fWidth);
             SkASSERT(layer->rect().height() == desc.fHeight);
         }
+#endif
         return false;
     }
 
@@ -166,7 +168,7 @@ bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool do
         // Hooray it is still in the atlas - make sure it stays there
         SkASSERT(!dontAtlas);
         layer->setLocked(true);
-        this->incPlotLock(layer->plot()->id());
+        fPlotLocks[layer->plot()->id()]++;
         return false;
     } else if (!dontAtlas && PlausiblyAtlasable(desc.fWidth, desc.fHeight)) {
         // Not in the atlas - will it fit?
@@ -191,7 +193,7 @@ bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool do
                 layer->setTexture(fAtlas->getTexture(), bounds);
                 layer->setPlot(plot);
                 layer->setLocked(true);
-                this->incPlotLock(layer->plot()->id());
+                fPlotLocks[layer->plot()->id()]++;
                 return true;
             }
 
@@ -217,7 +219,7 @@ bool GrLayerCache::lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool do
 void GrLayerCache::unlock(GrCachedLayer* layer) {
     SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas->getTexture(), layer);)
 
-    if (NULL == layer) {
+    if (NULL == layer || !layer->locked()) {
         // invalid or not locked
         return;
     }
@@ -225,7 +227,8 @@ void GrLayerCache::unlock(GrCachedLayer* layer) {
     if (layer->isAtlased()) {
         const int plotID = layer->plot()->id();
 
-        this->decPlotLock(plotID);
+        SkASSERT(fPlotLocks[plotID] > 0);
+        fPlotLocks[plotID]--;
         // At this point we could aggressively clear out un-locked plots but
         // by delaying we may be able to reuse some of the atlased layers later.
 #if DISABLE_CACHING
@@ -250,6 +253,9 @@ void GrLayerCache::unlock(GrCachedLayer* layer) {
 
 #ifdef SK_DEBUG
 void GrLayerCache::validate() const {
+    int plotLocks[kNumPlotsX * kNumPlotsY];
+    memset(plotLocks, 0, sizeof(plotLocks));
+
     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::ConstIter iter(&fLayerHash);
     for (; !iter.done(); ++iter) {
         const GrCachedLayer* layer = &(*iter);
@@ -264,7 +270,7 @@ void GrLayerCache::validate() const {
             SkASSERT(!pictInfo->fPlotUsage.isEmpty());
 #endif
         } else {
-            // If there is no picture info for this picture then all of its
+            // If there is no picture info for this layer then all of its
             // layers should be non-atlased.
             SkASSERT(!layer->isAtlased());
         }
@@ -276,10 +282,14 @@ void GrLayerCache::validate() const {
             SkASSERT(pictInfo->fPlotUsage.contains(layer->plot()));
 
             if (layer->locked()) {
-                SkASSERT(fPlotLocks[layer->plot()->id()] > 0);
+                plotLocks[layer->plot()->id()]++;
             }
         } 
     }
+
+    for (int i = 0; i < kNumPlotsX*kNumPlotsY; ++i) {
+        SkASSERT(plotLocks[i] == fPlotLocks[i]);
+    }
 }
 
 class GrAutoValidateCache : ::SkNoncopyable {