Fix build error with enable_backup_ref_ptr_instance_tracer=true

See https://crbug.com/387277990

patch/patch.cfg

@@ -761,5 +761,12 @@ patches = [
     # Expose Mojo Connector error state to Receiver disconnect handlers.
     # https://github.com/chromiumembedded/cef/issues/3664
     'name': 'mojo_connect_result_3664'
+  },
+  {
+    # Fix error: static assertion failed due to requirement 'sizeof(cc::Layer)
+    # == sizeof(cc::SameSizeAsLayer)' when building with
+    # enable_backup_ref_ptr_instance_tracer=true.
+    # https://issues.chromium.org/issues/387277990
+    'name': 'cc_layer_387277990'
   }
 ]

patch/patches/cc_layer_387277990.patch

@@ -0,0 +1,26 @@
+diff --git cc/layers/layer.cc cc/layers/layer.cc
+index f51e5495d95f5..cd6c1bb02f50c 100644
+--- cc/layers/layer.cc
++++ cc/layers/layer.cc
+@@ -50,16 +50,18 @@ struct SameSizeAsLayer : public base::RefCounted<SameSizeAsLayer>,
+   SameSizeAsLayer();
+   ~SameSizeAsLayer() override;
+ 
+-  void* pointers[4];
++  raw_ptr<void> raw_pointers[2];
++  std::unique_ptr<void> unique_pointers[2];
+ 
+   struct {
+     LayerList children;
+     gfx::Size bounds;
+-    unsigned bitfields;
++    HitTestOpaqueness hit_test_opaqueness;
++    bool bitfields;
+     SkColor4f background_color;
+     TouchActionRegion touch_action_region;
+     ElementId element_id;
+-    raw_ptr<void> rare_inputs;
++    std::unique_ptr<void> rare_inputs;
+   } inputs;
+   gfx::Rect update_rect;
+   int int_fields[7];