Bug 1512156 - Update webrender to commit 8a6a53883bc6fe9522730e09b916f4023ee10d51 (WR PR #3387). r=kats

servo/webrender#3387

Differential Revision: https://phabricator.services.mozilla.com/D13893

UltraBlame original commit: ea5869ddc7dc02086e3c36e48af7b9e8a26678ca

Author: marco-c

gfx/webrender_bindings/revision.txt

@@ -1 +1 @@
-7c4162c581978d1a72ed2271a94382290855e227
+8a6a53883bc6fe9522730e09b916f4023ee10d51

gfx/wr/webrender/src/render_backend.rs

@@ -1110,10 +1110,10 @@ impl RenderBackend {
             txn.blob_rasterizer = blob_rasterizer;
         }
 
-        if !transaction_msg.use_scene_builder_thread && txn.can_skip_scene_builder() {
-            if let Some(rasterizer) = txn.blob_rasterizer.take() {
-                self.resource_cache.set_blob_rasterizer(rasterizer);
-            }
+        if !transaction_msg.use_scene_builder_thread &&
+            txn.can_skip_scene_builder() &&
+            txn.blob_rasterizer.is_none() {
+
             self.update_document(
                 txn.document_id,
                 replace(&mut txn.resource_updates, Vec::new()),

gfx/wr/webrender/src/resource_cache.rs

@@ -1082,7 +1082,7 @@ impl ResourceCache {
         &mut self,
         keys: &[BlobImageKey]
     ) -> (Option<Box<AsyncBlobImageRasterizer>>, Vec<BlobImageParams>) {
-        if self.blob_image_handler.is_none() {
+        if self.blob_image_handler.is_none() || keys.is_empty() {
             return (None, Vec::new());
         }