Bug 1248913 - Add a constructor argument to nsDisplayMixBlendMode that lets you specify the blend mode. r=mattwoodrow

MozReview-Commit-ID: 9MqjLKjRmeh

--HG--
extra : rebase_source : 11ebc2d8fa1939ba079bdf09e916d3da1e68d6d7

layout/base/nsDisplayList.cpp

@@ -4319,8 +4319,10 @@ nsDisplayOpacity::WriteDebugInfo(std::stringstream& aStream)
 
 nsDisplayMixBlendMode::nsDisplayMixBlendMode(nsDisplayListBuilder* aBuilder,
                                              nsIFrame* aFrame, nsDisplayList* aList,
+                                             uint8_t aBlendMode,
                                              const DisplayItemScrollClip* aScrollClip)
   : nsDisplayWrapList(aBuilder, aFrame, aList, aScrollClip)
+  , mBlendMode(aBlendMode)
 {
   MOZ_COUNT_CTOR(nsDisplayMixBlendMode);
 }
@@ -4361,7 +4363,7 @@ nsDisplayMixBlendMode::BuildLayer(nsDisplayListBuilder* aBuilder,
     return nullptr;
   }
 
-  container->SetMixBlendMode(nsCSSRendering::GetGFXBlendMode(mFrame->StyleDisplay()->mMixBlendMode));
+  container->SetMixBlendMode(nsCSSRendering::GetGFXBlendMode(mBlendMode));
 
   return container.forget();
 }

layout/base/nsDisplayList.h

@@ -3385,7 +3385,7 @@ private:
 class nsDisplayMixBlendMode : public nsDisplayWrapList {
 public:
   nsDisplayMixBlendMode(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
-                        nsDisplayList* aList,
+                        nsDisplayList* aList, uint8_t aBlendMode,
                         const DisplayItemScrollClip* aScrollClip);
 #ifdef NS_BUILD_REFCNT_LOGGING
   virtual ~nsDisplayMixBlendMode();
@@ -3413,6 +3413,9 @@ public:
     return false;
   }
   NS_DISPLAY_DECL_NAME("MixBlendMode", TYPE_MIX_BLEND_MODE)
+
+private:
+  uint8_t mBlendMode;
 };
 
 class nsDisplayBlendContainer : public nsDisplayWrapList {

layout/generic/nsFrame.cpp

@@ -2314,6 +2314,7 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
     mixBlendClipState.Clear();
     resultList.AppendNewToTop(
         new (aBuilder) nsDisplayMixBlendMode(aBuilder, this, &resultList,
+                                             disp->mMixBlendMode,
                                              containerItemScrollClip));
   }