Bug 1355351 - Make pseudo-elements return the correct style via getComputedStyle

* Add a node property to access the ::before and ::after pseudo-elements
* Look for the frame for ::before and ::after pseudos
* Clean up pseudo-element props
* Simplify nsLayoutUtils callers, and make child iterators notice display: contents pseudos

Tag #1375

1 files changed, 31 insertions, 30 deletions

diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index b9778d36d..866fa148b 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -1832,11 +1832,7 @@ nsCSSFrameConstructor::CreateGeneratedContentItem(nsFrameConstructorState& aStat
              aPseudoElement == CSSPseudoElementType::after,
              "unexpected aPseudoElement");
 
-  // XXXbz is this ever true?
-  if (!aParentContent->IsElement()) {
-    NS_ERROR("Bogus generated content parent");
-    return;
-  }
+  MOZ_ASSERT(aParentContent->IsElement());
 
   StyleSetHandle styleSet = mPresShell->StyleSet();
 
@@ -1864,6 +1860,13 @@ nsCSSFrameConstructor::CreateGeneratedContentItem(nsFrameConstructorState& aStat
   nsresult rv = NS_NewXMLElement(getter_AddRefs(container), nodeInfo.forget());
   if (NS_FAILED(rv))
     return;
+
+  // Cleared when the pseudo is unbound from the tree, so no need to store a
+  // strong reference, nor a destructor.
+  nsIAtom* property = isBefore
+    ? nsGkAtoms::beforePseudoProperty : nsGkAtoms::afterPseudoProperty;
+  aParentContent->SetProperty(property, container.get());
+
   container->SetIsNativeAnonymousRoot();
   container->SetPseudoElementType(aPseudoElement);
 
@@ -6079,6 +6082,9 @@ AddGenConPseudoToFrame(nsIFrame* aOwnerFrame, nsIContent* aContent)
   NS_ASSERTION(nsLayoutUtils::IsFirstContinuationOrIBSplitSibling(aOwnerFrame),
                "property should only be set on first continuation/ib-sibling");
 
+  // FIXME(emilio): Remove this property, and use the frame of the generated
+  // content itself to tear the content down? It should be quite simpler.
+
   nsIFrame::ContentArray* value =
     aOwnerFrame->GetProperty(nsIFrame::GenConProperty());
   if (!value) {
@@ -6340,7 +6346,7 @@ AdjustAppendParentForAfterContent(nsFrameManager* aFrameManager,
   // frames to find the first one that is either a ::after frame for an
   // ancestor of aChild or a frame that is for a node later in the
   // document than aChild and return that in aAfterFrame.
-  if (aParentFrame->GetGenConPseudos() ||
+  if (aParentFrame->GetProperty(nsIFrame::GenConProperty()) ||
       nsLayoutUtils::HasPseudoStyle(aContainer, aParentFrame->StyleContext(),
                                     CSSPseudoElementType::after,
                                     aParentFrame->PresContext()) ||
@@ -6669,9 +6675,8 @@ nsCSSFrameConstructor::FindFrameForContentSibling(nsIContent* aContent,
   nsIFrame* sibling = aContent->GetPrimaryFrame();
   if (!sibling && GetDisplayContentsStyleFor(aContent)) {
     // A display:contents node - check if it has a ::before / ::after frame...
-    sibling = aPrevSibling ?
-      nsLayoutUtils::GetAfterFrameForContent(aParentFrame, aContent) :
-      nsLayoutUtils::GetBeforeFrameForContent(aParentFrame, aContent);
+    sibling = aPrevSibling ? nsLayoutUtils::GetAfterFrame(aContent)
+                           : nsLayoutUtils::GetBeforeFrame(aContent);
     if (!sibling) {
       // ... then recurse into children ...
       const bool forward = !aPrevSibling;
@@ -6682,9 +6687,8 @@ nsCSSFrameConstructor::FindFrameForContentSibling(nsIContent* aContent,
     }
     if (!sibling) {
       // ... then ::after / ::before on the opposite end.
-      sibling = aPrevSibling ?
-        nsLayoutUtils::GetBeforeFrameForContent(aParentFrame, aContent) :
-        nsLayoutUtils::GetAfterFrameForContent(aParentFrame, aContent);
+      sibling = aPrevSibling ? nsLayoutUtils::GetAfterFrame(aContent)
+                             : nsLayoutUtils::GetBeforeFrame(aContent);
     }
     if (!sibling) {
       return nullptr;
@@ -8291,26 +8295,23 @@ nsCSSFrameConstructor::ContentRemoved(nsIContent*  aContainer,
   MOZ_ASSERT(!childFrame || !GetDisplayContentsStyleFor(aChild),
              "display:contents nodes shouldn't have a frame");
   if (!childFrame && GetDisplayContentsStyleFor(aChild)) {
-    nsIFrame* ancestorFrame = nullptr;
     nsIContent* ancestor = aContainer;
-    for (; ancestor; ancestor = ancestor->GetParent()) {
-      ancestorFrame = ancestor->GetPrimaryFrame();
-      if (ancestorFrame) {
-        break;
-      }
+    while (!ancestor->GetPrimaryFrame()) {
+      // FIXME(emilio): Should this use the flattened tree parent instead?
+      ancestor = ancestor->GetParent();
+      MOZ_ASSERT(ancestor, "we can't have a display: contents subtree root!");
     }
-    if (ancestorFrame) {
-      nsIFrame* contentInsertion = ancestorFrame->GetContentInsertionFrame();
-      if (ancestorFrame->GetGenConPseudos() ||
-          (contentInsertion && contentInsertion->GetGenConPseudos())) {
-        *aDidReconstruct = true;
-        LAYOUT_PHASE_TEMP_EXIT();
-        // XXXmats Can we recreate frames only for the ::after/::before content?
-        // XXX Perhaps even only those that belong to the aChild sub-tree?
-        RecreateFramesForContent(ancestor, false, aFlags, aDestroyedFramesFor);
-        LAYOUT_PHASE_TEMP_REENTER();
-        return;
-      }
+
+    nsIFrame* ancestorFrame = ancestor->GetPrimaryFrame();
+    if (ancestorFrame->GetProperty(nsIFrame::GenConProperty())) {
+      *aDidReconstruct = true;
+      LAYOUT_PHASE_TEMP_EXIT();
+
+      // XXXmats Can we recreate frames only for the ::after/::before content?
+      // XXX Perhaps even only those that belong to the aChild sub-tree?
+      RecreateFramesForContent(ancestor, false, aFlags, aDestroyedFramesFor);
+      LAYOUT_PHASE_TEMP_REENTER();
+      return;
     }
 
     FlattenedChildIterator iter(aChild);