commit 4a74980d5d86
Author: J. Ryan Stinnett <jryans@gmail.com>
Date:   Fri Oct 20 15:24:51 2017 -0500

    Bug 1409277 - Ignore non-URLs for background pres attr. r=manishearth, a=ritu
    
    Check background attribute values for the same types (URL, image) in Stylo mode
    as we do in Gecko mode.
    
    In particular, this ignores the edge case of the empty attribute, which comes
    through as a string value type, and leads Stylo to trigger a load of the page
    itself as the background image (since the empty URL is interpreted as relative
    to the page).
    
    MozReview-Commit-ID: CUhq5nS8kVw
    
    --HG--
    extra : source : 1fe7b56a29c6a2cac69fc986c5fb4b99a92d7781
    extra : histedit_source : cc3086f60235d56bb69368fb754fd61c3dffe86f
---
 layout/style/ServoSpecifiedValues.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git layout/style/ServoSpecifiedValues.cpp layout/style/ServoSpecifiedValues.cpp
index bb8d425316b0..c374a6061ac9 100644
--- layout/style/ServoSpecifiedValues.cpp
+++ layout/style/ServoSpecifiedValues.cpp
@@ -121,6 +121,10 @@ ServoSpecifiedValues::SetTextDecorationColorOverride()
 void
 ServoSpecifiedValues::SetBackgroundImage(nsAttrValue& aValue)
 {
+  if (aValue.Type() != nsAttrValue::eURL &&
+      aValue.Type() != nsAttrValue::eImage) {
+    return;
+  }
   nsAutoString str;
   aValue.ToString(str);
   Servo_DeclarationBlock_SetBackgroundImage(