[chromium] Pass SkBitmap by reference in WebImageLayer::setBitmap

cc/blink/web_image_layer_impl.cc

Index: cc/blink/web_image_layer_impl.cc
diff --git a/cc/blink/web_image_layer_impl.cc b/cc/blink/web_image_layer_impl.cc
index b31d890dc2c618390850ece816ede74b0cea8259..818608d5c916984cacebb880a5c8c44d4308050d 100644
--- a/cc/blink/web_image_layer_impl.cc
+++ b/cc/blink/web_image_layer_impl.cc
@@ -26,6 +26,10 @@ blink::WebLayer* WebImageLayerImpl::layer() {
 }
 
 void WebImageLayerImpl::setBitmap(SkBitmap bitmap) {
+  setImageBitmap(bitmap);
+}
+
+void WebImageLayerImpl::setImageBitmap(const SkBitmap& bitmap) {
   if (WebLayerImpl::UsingPictureLayer()) {
     static_cast<cc::PictureImageLayer*>(layer_->layer())->SetBitmap(bitmap);
     static_cast<WebLayerImplFixedBounds*>(layer_.get())