Bug 399532 - "nsDisplayBackground::GetBounds() should take nsITheme overflow into account" [p=frnchfrgg-mozbugs@altern.org (_FrnchFrgg_) r+sr=roc a1.9=beltzner]

layout/base/nsDisplayList.cpp

@@ -461,7 +461,7 @@ void nsDisplayList::Sort(nsDisplayListBuilder* aBuilder,
 PRBool
 nsDisplayBackground::IsOpaque(nsDisplayListBuilder* aBuilder) {
   // theme background overrides any other background
-  if (mFrame->IsThemed())
+  if (mIsThemed)
     return PR_FALSE;
 
   PRBool isCanvas;
@@ -479,7 +479,7 @@ nsDisplayBackground::IsOpaque(nsDisplayListBuilder* aBuilder) {
 PRBool
 nsDisplayBackground::IsUniform(nsDisplayListBuilder* aBuilder) {
   // theme background overrides any other background
-  if (mFrame->IsThemed())
+  if (mIsThemed)
     return PR_FALSE;
 
   PRBool isCanvas;
@@ -532,6 +532,14 @@ nsDisplayBackground::Paint(nsDisplayListBuilder* aBuilder,
                                   mFrame->HonorPrintBackgroundSettings());
 }
 
+nsRect
+nsDisplayBackground::GetBounds(nsDisplayListBuilder* aBuilder) {
+  if (mIsThemed)
+    return mFrame->GetOverflowRect() + aBuilder->ToReferenceFrame(mFrame);
+
+  return nsRect(aBuilder->ToReferenceFrame(mFrame), mFrame->GetSize());
+}
+
 nsRect
 nsDisplayOutline::GetBounds(nsDisplayListBuilder* aBuilder) {
   return mFrame->GetOverflowRect() + aBuilder->ToReferenceFrame(mFrame);

layout/base/nsDisplayList.h

@@ -958,6 +958,7 @@ public:
 class nsDisplayBackground : public nsDisplayItem {
 public:
   nsDisplayBackground(nsIFrame* aFrame) : nsDisplayItem(aFrame) {
+    mIsThemed = mFrame->IsThemed();
     MOZ_COUNT_CTOR(nsDisplayBackground);
   }
 #ifdef NS_BUILD_REFCNT_LOGGING
@@ -971,9 +972,13 @@ public:
   virtual PRBool IsVaryingRelativeToFrame(nsDisplayListBuilder* aBuilder,
                                           nsIFrame* aAncestorFrame);
   virtual PRBool IsUniform(nsDisplayListBuilder* aBuilder);
+  virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder);
   virtual void Paint(nsDisplayListBuilder* aBuilder, nsIRenderingContext* aCtx,
      const nsRect& aDirtyRect);
   NS_DISPLAY_DECL_NAME("Background")
+private:
+    /* Used to cache mFrame->IsThemed() since it isn't a cheap call */
+    PRPackedBool mIsThemed;
 };
 
 /**