[Impeller] opt into exp canvas.

impeller/aiks/experimental_canvas.cc

@@ -419,6 +419,7 @@ void ExperimentalCanvas::SaveLayer(
       // Validation failures are logged in FlipBackdrop.
       return;
     }
+    FlushPendingClips();
 
     backdrop_filter_contents = backdrop_filter_proc(
         FilterInput::Make(std::move(input_texture)),
@@ -468,8 +469,6 @@ void ExperimentalCanvas::SaveLayer(
   clip_coverage_stack_.PushSubpass(subpass_coverage, GetClipHeight());
 
   if (backdrop_filter_contents) {
-    FlushPendingClips();
-
     // Render the backdrop entity.
     Entity backdrop_entity;
     backdrop_entity.SetContents(std::move(backdrop_filter_contents));
@@ -759,7 +758,6 @@ void ExperimentalCanvas::AddRenderEntityToCurrentPass(Entity entity,
       if (!input_texture) {
         return;
       }
-
       FlushPendingClips();
 
       // The coverage hint tells the rendered Contents which portion of the

impeller/display_list/dl_dispatcher.cc

@@ -54,8 +54,9 @@ namespace impeller {
 // The watchdog object allocated here will automatically double-check
 // the depth usage at any exit point to the function, or any other
 // point at which it falls out of scope.
-#define AUTO_DEPTH_WATCHER(d) \
-  DepthWatcher _watcher(__FILE__, __LINE__, GetCanvas(), d)
+#define AUTO_DEPTH_WATCHER(d)                            \
+  DepthWatcher _watcher(__FILE__, __LINE__, GetCanvas(), \
+                        paint_.mask_blur_descriptor.has_value(), d)
 
 // While the AUTO_DEPTH_WATCHER macro will check the depth usage at
 // any exit point from the dispatch function, sometimes the dispatch
@@ -75,11 +76,12 @@ struct DepthWatcher {
   DepthWatcher(const std::string& file,
                int line,
                const impeller::Canvas& canvas,
+               bool has_mask_blur,
                int allowed)
       : file_(file),
         line_(line),
         canvas_(canvas),
-        allowed_(allowed),
+        allowed_(has_mask_blur ? allowed : (allowed + 1)),
         old_depth_(canvas.GetOpDepth()),
         old_max_(canvas.GetMaxOpDepth()) {}