Bug 1403073 - stylo: Fix some bindgen object layout issues. r=xidorn

MozReview-Commit-ID: CnW4J2ZlmfJ

--HG--
extra : rebase_source : 1a5318e75b1cde9a48dcdab689c7983a0b0c89b5

layout/style/ServoBindings.toml

@@ -346,6 +346,7 @@ opaque-types = [
     "StyleAnimationValue", # pulls in a whole bunch of stuff we don't need in the bindings
     "mozilla::dom::.*Callback", # Pulls in ErrorResult and other things that
                                 # don't align properly on Linux 32-bit
+    "mozilla::SchedulerGroup", # Non-standard-layout packing of field into superclass
 ]
 mapped-generic-types = [
     { generic = true, gecko = "mozilla::ServoUnsafeCell", servo = "::std::cell::UnsafeCell" },

layout/style/nsCSSValue.h

@@ -199,6 +199,11 @@ private:
   mutable bool mUsingRustString;
 
 protected:
+  // Only used by ImageValue.  Declared up here because otherwise bindgen gets
+  // confused by the non-standard-layout packing of the variable up into
+  // URLValueData.
+  bool mLoadedImage = false;
+
   virtual ~URLValueData();
 
   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
@@ -267,9 +272,6 @@ struct ImageValue final : public URLValueData
 protected:
   ~ImageValue();
 
-private:
-  bool mLoadedImage = false;
-
 public:
   // Inherit Equals from URLValueData