Backed out 3 changesets (bug 1344398) for assertion failures at Element.cpp a=backout

Backed out changeset d0e5a5ba01b5 (bug 1344398)
Backed out changeset d70f9de401d1 (bug 1344398)
Backed out changeset 647d0bb3714d (bug 1344398)

MozReview-Commit-ID: DTVWf28NcNb

dom/base/Element.cpp

@@ -1805,24 +1805,6 @@ Element::UnbindFromTree(bool aDeep, bool aNullParent)
     SetParentIsContent(false);
   }
 
-#ifdef DEBUG
-  // If we can get access to the PresContext, then we sanity-check that
-  // we're not leaving behind a pointer to ourselves as the PresContext's
-  // cached provider of the viewport's scrollbar styles.
-  if (document) {
-    nsIPresShell* presShell = document->GetShell();
-    if (presShell) {
-      nsPresContext* presContext = presShell->GetPresContext();
-      if (presContext) {
-        MOZ_ASSERT(this !=
-                   presContext->GetViewportScrollbarStylesOverrideNode(),
-                   "Leaving behind a raw pointer to this node (as having "
-                   "propagated scrollbar styles) - that's dangerous...");
-      }
-    }
-  }
-#endif
-
   // Ensure that CSS transitions don't continue on an element at a
   // different place in the tree (even if reinserted before next
   // animation refresh).

layout/base/RestyleManager.cpp

@@ -454,7 +454,7 @@ RestyleManager::ChangeHintToString(nsChangeHint aHint)
     "NeutralChange", "InvalidateRenderingObservers",
     "ReflowChangesSizeOrPosition", "UpdateComputedBSize",
     "UpdateUsesOpacity", "UpdateBackgroundPosition",
-    "AddOrRemoveTransform", "CSSOverflowChange",
+    "AddOrRemoveTransform"
   };
   static_assert(nsChangeHint_AllHints == (1 << ArrayLength(names)) - 1,
                 "Name list doesn't match change hints.");
@@ -1348,62 +1348,6 @@ RestyleManager::ProcessRestyledFrames(nsStyleChangeList& aChangeList)
   FramePropertyTable* propTable = presContext->PropertyTable();
   nsCSSFrameConstructor* frameConstructor = presContext->FrameConstructor();
 
-  // Handle nsChangeHint_CSSOverflowChange, by either updating the
-  // scrollbars on the viewport, or upgrading the change hint to frame-reconstruct.
-  for (nsStyleChangeData& data : aChangeList) {
-    if (data.mHint & nsChangeHint_CSSOverflowChange) {
-      data.mHint &= ~nsChangeHint_CSSOverflowChange;
-      bool doReconstruct = true; // assume the worst
-
-      // Only bother with this if we're html/body, since:
-      //  (a) It'd be *expensive* to reframe these particular nodes.  They're
-      //      at the root, so reframing would mean rebuilding the world.
-      //  (b) It's often *unnecessary* to reframe for "overflow" changes on
-      //      these particular nodes.  In general, the only reason we reframe
-      //      for "overflow" changes is so we can construct (or destroy) a
-      //      scrollframe & scrollbars -- and the html/body nodes often don't
-      //      need their own scrollframe/scrollbars because they coopt the ones
-      //      on the viewport (which always exist). So depending on whether
-      //      that's happening, we can skip the reframe for these nodes.
-      if (data.mContent->IsAnyOfHTMLElements(nsGkAtoms::body,
-                                             nsGkAtoms::html)) {
-        // If the restyled element provided/provides the scrollbar styles for
-        // the viewport before and/or after this restyle, AND it's not coopting
-        // that responsibility from some other element (which would need
-        // reconstruction to make its own scrollframe now), THEN: we don't need
-        // to reconstruct - we can just reflow, because no scrollframe is being
-        // added/removed.
-        nsIContent* prevOverrideNode =
-          presContext->GetViewportScrollbarStylesOverrideNode();
-        nsIContent* newOverrideNode =
-          presContext->UpdateViewportScrollbarStylesOverride();
-
-        if (data.mContent == prevOverrideNode ||
-            data.mContent == newOverrideNode) {
-          // If we get here, the restyled element provided the scrollbar styles
-          // for viewport before this restyle, OR it will provide them after.
-          if (!prevOverrideNode || !newOverrideNode ||
-              prevOverrideNode == newOverrideNode) {
-            // If we get here, the restyled element is NOT replacing (or being
-            // replaced by) some other element as the viewport's
-            // scrollbar-styles provider. (If it were, we'd potentially need to
-            // reframe to create a dedicated scrollframe for whichever element
-            // is being booted from providing viewport scrollbar styles.)
-            //
-            // Under these conditions, we're OK to assume that this "overflow"
-            // change only impacts the root viewport's scrollframe, which
-            // already exists, so we can simply reflow instead of reframing.
-            data.mHint |= nsChangeHint_AllReflowHints;
-            doReconstruct = false;
-          }
-        }
-      }
-      if (doReconstruct) {
-        data.mHint |= nsChangeHint_ReconstructFrame;
-      }
-    }
-  }
-
   // Make sure to not rebuild quote or counter lists while we're
   // processing restyles
   frameConstructor->BeginUpdate();

layout/base/nsCSSFrameConstructor.cpp

@@ -8488,19 +8488,11 @@ nsCSSFrameConstructor::ContentRemoved(nsIContent*  aContainer,
     ServoRestyleManager::ClearServoDataFromSubtree(aChild->AsElement());
   }
 
-  nsPresContext* presContext = mPresShell->GetPresContext();
-  MOZ_ASSERT(presContext, "Our presShell should have a valid presContext");
-
   if (aChild->IsHTMLElement(nsGkAtoms::body) ||
       (!aContainer && aChild->IsElement())) {
-    // We might be removing the element that we propagated viewport scrollbar
+    // This might be the element we propagated viewport scrollbar
-    // styles from.  Recompute those. (This clause covers two of the three
+    // styles from.  Recompute those.
-    // possible scrollbar-propagation sources: the <body> [as aChild or a
+    mPresShell->GetPresContext()->UpdateViewportScrollbarStylesOverride();
-    // descendant] and the root node. The other possible scrollbar-propagation
-    // source is a fullscreen element, and we have code elsewhere to update
-    // scrollbars after fullscreen elements are removed -- specifically, it's
-    // part of the fullscreen cleanup code called by Element::UnbindFromTree.)
-    presContext->UpdateViewportScrollbarStylesOverride();
   }
 
   // XXXldb Do we need to re-resolve style to handle the CSS2 + combinator and
@@ -8562,6 +8554,7 @@ nsCSSFrameConstructor::ContentRemoved(nsIContent*  aContainer,
     ClearDisplayContentsIn(aChild, aContainer);
   }
 
+  nsPresContext* presContext = mPresShell->GetPresContext();
 #ifdef MOZ_XUL
   if (NotifyListBoxBody(presContext, aContainer, aChild, aOldNextSibling,
                         childFrame, CONTENT_REMOVED)) {

layout/base/nsChangeHint.h

@@ -222,16 +222,6 @@ enum nsChangeHint : uint32_t {
    */
   nsChangeHint_AddOrRemoveTransform = 1 << 27,
 
-  /**
-   * Indicates that the overflow-x and/or overflow-y property changed.
-   *
-   * In most cases, this is equivalent to nsChangeHint_ReconstructFrame. But
-   * in some special cases where the change is really targeting the viewport's
-   * scrollframe, this is instead equivalent to nsChangeHint_AllReflowHints
-   * (because the viewport always has an associated scrollframe).
-   */
-  nsChangeHint_CSSOverflowChange = 1 << 28,
-
   // IMPORTANT NOTE: When adding a new hint, you will need to add it to
   // one of:
   //
@@ -247,7 +237,7 @@ enum nsChangeHint : uint32_t {
   /**
    * Dummy hint value for all hints. It exists for compile time check.
    */
-  nsChangeHint_AllHints = (1 << 29) - 1,
+  nsChangeHint_AllHints = (1 << 28) - 1,
 };
 
 // Redefine these operators to return nothing. This will catch any use
@@ -336,7 +326,6 @@ inline nsChangeHint operator^=(nsChangeHint& aLeft, nsChangeHint aRight)
 #define nsChangeHint_Hints_NeverHandledForDescendants (    \
   nsChangeHint_BorderStyleNoneChange |                     \
   nsChangeHint_ChildrenOnlyTransform |                     \
-  nsChangeHint_CSSOverflowChange |                         \
   nsChangeHint_InvalidateRenderingObservers |              \
   nsChangeHint_RecomputePosition |                         \
   nsChangeHint_UpdateBackgroundPosition |                  \

layout/base/nsPresContext.cpp

@@ -231,7 +231,6 @@ nsPresContext::nsPresContext(nsIDocument* aDocument, nsPresContextType aType)
     mFocusBackgroundColor(mBackgroundColor),
     mFocusTextColor(mDefaultColor),
     mBodyTextColor(mDefaultColor),
-    mViewportScrollbarOverrideNode(nullptr),
     mViewportStyleScrollbar(NS_STYLE_OVERFLOW_AUTO, NS_STYLE_OVERFLOW_AUTO),
     mFocusRingWidth(1),
     mExistThrottledUpdates(false),
@@ -1497,10 +1496,10 @@ nsPresContext::UpdateViewportScrollbarStylesOverride()
   // Start off with our default styles, and then update them as needed.
   mViewportStyleScrollbar = ScrollbarStyles(NS_STYLE_OVERFLOW_AUTO,
                                             NS_STYLE_OVERFLOW_AUTO);
-  mViewportScrollbarOverrideNode = nullptr;
+  nsIContent* propagatedFrom = nullptr;
   // Don't propagate the scrollbar state in printing or print preview.
   if (!IsPaginated()) {
-    mViewportScrollbarOverrideNode =
+    propagatedFrom =
       GetPropagatedScrollbarStylesForViewport(this, &mViewportStyleScrollbar);
   }
 
@@ -1512,12 +1511,13 @@ nsPresContext::UpdateViewportScrollbarStylesOverride()
     // the styles are from, so that the state of those elements is not
     // affected across fullscreen change.
     if (fullscreenElement != document->GetRootElement() &&
-        fullscreenElement != mViewportScrollbarOverrideNode) {
+        fullscreenElement != propagatedFrom) {
       mViewportStyleScrollbar = ScrollbarStyles(NS_STYLE_OVERFLOW_HIDDEN,
                                                 NS_STYLE_OVERFLOW_HIDDEN);
     }
   }
-  return mViewportScrollbarOverrideNode;
+
+  return propagatedFrom;
 }
 
 bool

layout/base/nsPresContext.h

@@ -737,18 +737,7 @@ public:
    *         it was propagated from.
    */
   nsIContent* UpdateViewportScrollbarStylesOverride();
-
+  const ScrollbarStyles& GetViewportScrollbarStylesOverride()
-  /**
-   * Returns the cached result from the last call to
-   * UpdateViewportScrollbarStylesOverride() -- i.e. return the node
-   * whose scrollbar styles we have propagated to the viewport (or nullptr if
-   * there is no such node).
-   */
-  nsIContent* GetViewportScrollbarStylesOverrideNode() const {
-    return mViewportScrollbarOverrideNode;
-  }
-
-  const ScrollbarStyles& GetViewportScrollbarStylesOverride() const
   {
     return mViewportStyleScrollbar;
   }
@@ -1396,16 +1385,7 @@ protected:
 
   nscolor               mBodyTextColor;
 
-  // This is a non-owning pointer. May be null. If non-null, it's guaranteed
-  // to be pointing to a node that's still alive, because we'll reset it in
-  // UpdateViewportScrollbarStylesOverride() as part of the cleanup code
-  // when this node is removed from the document. (For <body> and the root node,
-  // this call happens in nsCSSFrameConstructor::ContentRemoved(). For
-  // fullscreen elements, it happens in the fullscreen-specific cleanup
-  // invoked by Element::UnbindFromTree().)
-  nsIContent* MOZ_NON_OWNING_REF mViewportScrollbarOverrideNode;
   ScrollbarStyles       mViewportStyleScrollbar;
-
   uint8_t               mFocusRingWidth;
 
   bool mExistThrottledUpdates;

layout/reftests/scrolling/propagated-overflow-style-1-ref.html

@@ -1,18 +0,0 @@
-<!DOCTYPE html>
-<html>
-<head>
-  <title>
-    Reference case with body and html *independently* scrollable.
-  </title>
-  <style>
-    html {
-      overflow: scroll;
-    }
-    body {
-      overflow: scroll;
-    }
-  </style>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-1a.html

@@ -1,23 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with body and html *independently* scrollable,
-    with body's "overflow" set dynamically.
-  </title>
-  <style>
-    html {
-      overflow: scroll;
-    }
-  </style>
-  <script>
-    function doTest() {
-      document.body.style.overflow = "scroll";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-1b.html

@@ -1,23 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with body and html *independently* scrollable,
-    with html's "overflow" set dynamically.
-  </title>
-  <style>
-    body {
-      overflow: scroll;
-    }
-  </style>
-  <script>
-    function doTest() {
-      document.documentElement.style.overflow = "scroll";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-1c.html

@@ -1,19 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with body and html *independently* scrollable,
-    with both html & body's "overflow" set dynamically.
-  </title>
-  <script>
-    function doTest() {
-      document.documentElement.style.overflow = "scroll";
-      document.body.style.overflow = "scroll";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-2-ref.html

@@ -1,15 +0,0 @@
-<!DOCTYPE html>
-<html>
-<head>
-  <title>
-    Reference case with the root viewport scrollable, via styles on html node.
-  </title>
-  <style>
-    html {
-      overflow: scroll;
-    }
-  </style>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-2a.html

@@ -1,26 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with only one of [html,body] being scrollable,
-    after body's "overflow" is reset dynamically.
-  </title>
-  <style>
-    html {
-      overflow: scroll;
-    }
-    body {
-      overflow: scroll;
-    }
-  </style>
-  <script>
-    function doTest() {
-      document.body.style.overflow = "visible";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-2b.html

@@ -1,26 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with only one of [html,body] being scrollable,
-    after html's "overflow" is reset dynamically.
-  </title>
-  <style>
-    html {
-      overflow: scroll;
-    }
-    body {
-      overflow: scroll;
-    }
-  </style>
-  <script>
-    function doTest() {
-      document.documentElement.style.overflow = "visible";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-2c.html

@@ -1,24 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with only one of [html,body] being scrollable,
-    with their "overflow" styles being dynamically swapped.
-  </title>
-  <style>
-    html {
-      overflow: scroll;
-    }
-  </style>
-  <script>
-    function doTest() {
-      document.documentElement.style.overflow = "visible";
-      document.body.style.overflow = "scroll";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-2d.html

@@ -1,24 +0,0 @@
-<!DOCTYPE html>
-<html class="reftest-wait">
-<head>
-  <title>
-    Testcase with only one of [html,body] being scrollable,
-    with their "overflow" styles being dynamically swapped.
-  </title>
-  <style>
-    body {
-      overflow: scroll;
-    }
-  </style>
-  <script>
-    function doTest() {
-      document.documentElement.style.overflow = "scroll";
-      document.body.style.overflow = "visible";
-      document.documentElement.removeAttribute("class");
-    }
-    window.addEventListener("MozReftestInvalidate", doTest);
-  </script>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/propagated-overflow-style-2e.html

@@ -1,15 +0,0 @@
-<!DOCTYPE html>
-<html>
-<head>
-  <title>
-    Testcase with the root viewport scrollable, via styles on body node.
-  </title>
-  <style>
-    body {
-      overflow: scroll;
-    }
-  </style>
-</head>
-<body>
-</body>
-</html>

layout/reftests/scrolling/reftest.list

@@ -86,13 +86,3 @@ fuzzy-if(asyncPan&&!layersGPUAccelerated,102,2420) == frame-scrolling-attr-2.htm
 == fractional-scroll-area.html?top=0.4&outerBottom=99.6&innerBottom=200.4&scrollBefore=999 fractional-scroll-area.html?top=0&outerBottom=100&innerBottom=200&scrollBefore=999
 == fractional-scroll-area.html?top=0.4&outerBottom=100.4&innerBottom=200.4&scrollBefore=999 fractional-scroll-area.html?top=0&outerBottom=100&innerBottom=200&scrollBefore=999
 != fractional-scroll-area-invalidation.html about:blank
-
-# Tests for "overflow" styles that may be propagated to the viewport:
-== propagated-overflow-style-1a.html propagated-overflow-style-1-ref.html
-== propagated-overflow-style-1b.html propagated-overflow-style-1-ref.html
-== propagated-overflow-style-1c.html propagated-overflow-style-1-ref.html
-== propagated-overflow-style-2a.html propagated-overflow-style-2-ref.html
-== propagated-overflow-style-2b.html propagated-overflow-style-2-ref.html
-== propagated-overflow-style-2c.html propagated-overflow-style-2-ref.html
-== propagated-overflow-style-2d.html propagated-overflow-style-2-ref.html
-== propagated-overflow-style-2e.html propagated-overflow-style-2-ref.html

layout/style/nsStyleStruct.cpp

@@ -3488,6 +3488,8 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
       || mDisplay != aNewData.mDisplay
       || mContain != aNewData.mContain
       || (mFloat == StyleFloat::None) != (aNewData.mFloat == StyleFloat::None)
+      || mOverflowX != aNewData.mOverflowX
+      || mOverflowY != aNewData.mOverflowY
       || mScrollBehavior != aNewData.mScrollBehavior
       || mScrollSnapTypeX != aNewData.mScrollSnapTypeX
       || mScrollSnapTypeY != aNewData.mScrollSnapTypeY
@@ -3499,11 +3501,6 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
     hint |= nsChangeHint_ReconstructFrame;
   }
 
-  if (mOverflowX != aNewData.mOverflowX
-      || mOverflowY != aNewData.mOverflowY) {
-    hint |= nsChangeHint_CSSOverflowChange;
-  }
-
   /* Note: When mScrollBehavior, mScrollSnapTypeX, mScrollSnapTypeY,
    * mScrollSnapPointsX, mScrollSnapPointsY, or mScrollSnapDestination are
    * changed, nsChangeHint_NeutralChange is not sufficient to enter

layout/style/test/test_dynamic_change_causing_reflow.html

@@ -95,90 +95,6 @@ const gTestcases = [
     expectReflow: true,
   },
 
-  // * Changing 'overflow' on <body> should cause reflow,
-  // but not frame reconstruction
-  {
-    elem: document.body,
-    /* beforeStyle: implicitly 'overflow:visible' */
-    afterStyle:  "overflow: hidden",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.body,
-    /* beforeStyle: implicitly 'overflow:visible' */
-    afterStyle:  "overflow: scroll",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.body,
-    beforeStyle: "overflow: hidden",
-    afterStyle:  "overflow: auto",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.body,
-    beforeStyle: "overflow: hidden",
-    afterStyle:  "overflow: scroll",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.body,
-    beforeStyle: "overflow: hidden",
-    afterStyle:  "overflow: visible",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.body,
-    beforeStyle: "overflow: auto",
-    afterStyle:  "overflow: hidden",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.body,
-    beforeStyle: "overflow: visible",
-    afterStyle:  "overflow: hidden",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-
-  // * Changing 'overflow' on <html> should cause reflow,
-  // but not frame reconstruction
-  {
-    elem: document.documentElement,
-    /* beforeStyle: implicitly 'overflow:visible' */
-    afterStyle:  "overflow: auto",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-  {
-    elem: document.documentElement,
-    beforeStyle: "overflow: visible",
-    afterStyle:  "overflow: auto",
-    expectConstruction: false,
-    expectReflow: true,
-  },
-
-  // * Setting 'overflow' on arbitrary node should cause reflow as well as
-  // frame reconstruction
-  {
-    /* beforeStyle: implicitly 'overflow:visible' */
-    afterStyle:  "overflow: auto",
-    expectConstruction: true,
-    expectReflow: true,
-  },
-  {
-    beforeStyle: "overflow: auto",
-    afterStyle:  "overflow: visible",
-    expectConstruction: true,
-    expectReflow: true,
-  },
-
   // * Changing 'display' should cause frame construction and reflow.
   {
     beforeStyle: "display: inline",
@@ -219,35 +135,23 @@ function runOneTest(aTestcase)
     return;
   }
 
-  // Figure out which element we'll be tweaking (defaulting to gElem)
-  let elem = aTestcase.elem ?
-    aTestcase.elem : gElem;
-
-  // Verify that 'style' attribute is unset (avoid causing ourselves trouble):
-  if (elem.hasAttribute("style")) {
-    ok(false,
-       "test element has 'style' attribute already set! We're going to stomp " +
-       "on whatever's there when we clean up...");
-  }
-
   // Set the "before" style, and compose the first part of the message
   // to be used in our "is"/"isnot" invocations:
   let msgPrefix = "Changing style ";
   if (aTestcase.beforeStyle) {
-    elem.setAttribute("style", aTestcase.beforeStyle);
+    gElem.setAttribute("style", aTestcase.beforeStyle);
     msgPrefix += "from '" + aTestcase.beforeStyle + "' ";
   }
   msgPrefix += "to '" + aTestcase.afterStyle + "' ";
-  msgPrefix += "on " + elem.nodeName + " ";
 
   // Establish initial counts:
-  let unusedVal = elem.offsetHeight; // flush layout
+  let unusedVal = gElem.offsetHeight; // flush layout
   let origFramesConstructed = gUtils.framesConstructed;
   let origFramesReflowed = gUtils.framesReflowed;
 
   // Make the change and flush:
-  elem.setAttribute("style", aTestcase.afterStyle);
+  gElem.setAttribute("style", aTestcase.afterStyle);
-  unusedVal = elem.offsetHeight; // flush layout
+  unusedVal = gElem.offsetHeight; // flush layout
 
   // Make our is/isnot assertions about whether things should have changed:
   checkFinalCount(gUtils.framesConstructed, origFramesConstructed,
@@ -258,7 +162,7 @@ function runOneTest(aTestcase)
                   "reflow");
 
   // Clean up!
-  elem.removeAttribute("style");
+  gElem.removeAttribute("style");
 }
 
 gTestcases.forEach(runOneTest);