Clamps to invalidation region of a PictureLayer to the layer bounds to avoid adding unecessary bulk

cc/picture_layer.cc

Index: cc/picture_layer.cc
diff --git a/cc/picture_layer.cc b/cc/picture_layer.cc
index 4f192da7e180fdb51eaa7071aaad1d5107143fce..7924739259a2dc3b748977a0522d2c575fb7d85f 100644
--- a/cc/picture_layer.cc
+++ b/cc/picture_layer.cc
@@ -51,7 +51,11 @@ void PictureLayer::setLayerTreeHost(LayerTreeHost* host) {
 
 void PictureLayer::setNeedsDisplayRect(const gfx::RectF& layer_rect) {
   gfx::Rect rect = gfx::ToEnclosedRect(layer_rect);
-  pending_invalidation_.Union(rect);
+  if (!rect.IsEmpty()) {
+    // Clamp invalidation to the layer bounds.
+    rect.Intersect(gfx::Rect(bounds()));
+    pending_invalidation_.Union(rect);
+  }
   Layer::setNeedsDisplayRect(layer_rect);
 }