Revert of Fix bug in plot locking system

src/gpu/GrLayerCache.h

Index: src/gpu/GrLayerCache.h
diff --git a/src/gpu/GrLayerCache.h b/src/gpu/GrLayerCache.h
index 7bc98b0216972d936582e7002e5a6a47a506c713..790b82a8f3e74651ca52efae623ab7e6de9012fe 100644
--- a/src/gpu/GrLayerCache.h
+++ b/src/gpu/GrLayerCache.h
@@ -231,10 +231,9 @@
     // This implements a plot-centric locking mechanism (since the atlas
     // backing texture is always locked). Each layer that is locked (i.e.,
     // needed for the current rendering) in a plot increments the plot lock
-    // count for that plot for each time it is used. Similarly, once a 
-    // rendering is complete all the layers used in it decrement the lock
-    // count for the used plots. Plots with a 0 lock count are open for 
-    // recycling/purging.
+    // count for that plot. Similarly, once a rendering is complete all the
+    // layers used in it decrement the lock count for the used plots.
+    // Plots with a 0 lock count are open for recycling/purging.
     int fPlotLocks[kNumPlotsX * kNumPlotsY];
 
     void initAtlas();
@@ -256,12 +255,6 @@
     // was purged; false otherwise.
     bool purgePlot();
 
-    void incPlotLock(int plotIdx) { ++fPlotLocks[plotIdx]; }
-    void decPlotLock(int plotIdx) {
-        SkASSERT(fPlotLocks[plotIdx] > 0);
-        --fPlotLocks[plotIdx];
-    }
-
     // for testing
     friend class TestingAccess;
     int numLayers() const { return fLayerHash.count(); }