Add additional clean up code in MPD path

src/gpu/GrLayerCache.cpp

Index: src/gpu/GrLayerCache.cpp
diff --git a/src/gpu/GrLayerCache.cpp b/src/gpu/GrLayerCache.cpp
index 5374d115ca56d2c7168d45055a2ca974a9df64f0..c34751218869bd82e120432ace70b16183c25003 100644
--- a/src/gpu/GrLayerCache.cpp
+++ b/src/gpu/GrLayerCache.cpp
@@ -226,6 +226,11 @@ bool GrLayerCache::tryToAtlas(GrCachedLayer* layer,
                 break;  // We weren't able to purge any plots
             }
         }
+
+        if (pictInfo->fPlotUsage.isEmpty()) {
+            fPictureHash.remove(pictInfo->fPictureID);
+            SkDELETE(pictInfo);
+        }
     }
 
     return false;