cc: Prevent small scale factors (below 1) from being used or saved as the layer's rasterScale.

cc/layer_tree_host_common.cc

Index: cc/layer_tree_host_common.cc
diff --git a/cc/layer_tree_host_common.cc b/cc/layer_tree_host_common.cc
index e64a339aa8c2f3d7afc0848bdd401e50336f015c..a7dd4c8a24ee17f95a3bbdaf09e57df47f66520a 100644
--- a/cc/layer_tree_host_common.cc
+++ b/cc/layer_tree_host_common.cc
@@ -363,7 +363,11 @@ static inline void updateLayerContentsScale(Layer* layer, const WebTransformatio
             rasterScale = combinedScale / deviceScaleFactor;
             if (!layer->boundsContainPageScale())
                 rasterScale /= pageScaleFactor;
-            layer->setRasterScale(rasterScale);
+            // Prevent scale factors below 1 from being used or saved.
+            if (rasterScale < 1)
+                rasterScale = 1;
+            else
+                layer->setRasterScale(rasterScale);
         }
     }