Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 965 insertions, 0 deletions

diff --git a/layout/forms/nsComboboxControlFrame.cpp b/layout/forms/nsComboboxControlFrame.cpp
new file mode 100644
index 0000000000..a935e3c761
--- /dev/null
+++ b/layout/forms/nsComboboxControlFrame.cpp
@@ -0,0 +1,965 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsComboboxControlFrame.h"
+
+#include "gfxContext.h"
+#include "gfxUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "nsCOMPtr.h"
+#include "nsDeviceContext.h"
+#include "nsFocusManager.h"
+#include "nsCheckboxRadioFrame.h"
+#include "nsGkAtoms.h"
+#include "nsCSSAnonBoxes.h"
+#include "nsHTMLParts.h"
+#include "nsIFormControl.h"
+#include "nsILayoutHistoryState.h"
+#include "nsNameSpaceManager.h"
+#include "nsListControlFrame.h"
+#include "nsPIDOMWindow.h"
+#include "mozilla/PresState.h"
+#include "nsView.h"
+#include "nsViewManager.h"
+#include "nsIContentInlines.h"
+#include "nsIDOMEventListener.h"
+#include "nsISelectControlFrame.h"
+#include "nsContentUtils.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/HTMLSelectElement.h"
+#include "mozilla/dom/Document.h"
+#include "nsIScrollableFrame.h"
+#include "mozilla/ServoStyleSet.h"
+#include "nsNodeInfoManager.h"
+#include "nsContentCreatorFunctions.h"
+#include "nsLayoutUtils.h"
+#include "nsDisplayList.h"
+#include "nsITheme.h"
+#include "nsStyleConsts.h"
+#include "nsTextFrameUtils.h"
+#include "nsTextRunTransformations.h"
+#include "HTMLSelectEventListener.h"
+#include "mozilla/Likely.h"
+#include <algorithm>
+#include "nsTextNode.h"
+#include "mozilla/AsyncEventDispatcher.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/PresShellInlines.h"
+#include "mozilla/Unused.h"
+#include "gfx2DGlue.h"
+#include "mozilla/widget/nsAutoRollup.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+NS_IMETHODIMP
+nsComboboxControlFrame::RedisplayTextEvent::Run() {
+  if (mControlFrame) mControlFrame->HandleRedisplayTextEvent();
+  return NS_OK;
+}
+
+// Drop down list event management.
+// The combo box uses the following strategy for managing the drop-down list.
+// If the combo box or its arrow button is clicked on the drop-down list is
+// displayed If mouse exits the combo box with the drop-down list displayed the
+// drop-down list is asked to capture events The drop-down list will capture all
+// events including mouse down and up and will always return with
+// ListWasSelected method call regardless of whether an item in the list was
+// actually selected.
+// The ListWasSelected code will turn off mouse-capture for the drop-down list.
+// The drop-down list does not explicitly set capture when it is in the
+// drop-down mode.
+
+nsComboboxControlFrame* NS_NewComboboxControlFrame(PresShell* aPresShell,
+                                                   ComputedStyle* aStyle) {
+  nsComboboxControlFrame* it = new (aPresShell)
+      nsComboboxControlFrame(aStyle, aPresShell->GetPresContext());
+  return it;
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsComboboxControlFrame)
+
+//-----------------------------------------------------------
+// Reflow Debugging Macros
+// These let us "see" how many reflow counts are happening
+//-----------------------------------------------------------
+#ifdef DO_REFLOW_COUNTER
+
+#  define MAX_REFLOW_CNT 1024
+static int32_t gTotalReqs = 0;
+;
+static int32_t gTotalReflows = 0;
+;
+static int32_t gReflowControlCntRQ[MAX_REFLOW_CNT];
+static int32_t gReflowControlCnt[MAX_REFLOW_CNT];
+static int32_t gReflowInx = -1;
+
+#  define REFLOW_COUNTER() \
+    if (mReflowId > -1) gReflowControlCnt[mReflowId]++;
+
+#  define REFLOW_COUNTER_REQUEST() \
+    if (mReflowId > -1) gReflowControlCntRQ[mReflowId]++;
+
+#  define REFLOW_COUNTER_DUMP(__desc)                                   \
+    if (mReflowId > -1) {                                               \
+      gTotalReqs += gReflowControlCntRQ[mReflowId];                     \
+      gTotalReflows += gReflowControlCnt[mReflowId];                    \
+      printf("** Id:%5d %s RF: %d RQ: %d   %d/%d  %5.2f\n", mReflowId,  \
+             (__desc), gReflowControlCnt[mReflowId],                    \
+             gReflowControlCntRQ[mReflowId], gTotalReflows, gTotalReqs, \
+             float(gTotalReflows) / float(gTotalReqs) * 100.0f);        \
+    }
+
+#  define REFLOW_COUNTER_INIT()           \
+    if (gReflowInx < MAX_REFLOW_CNT) {    \
+      gReflowInx++;                       \
+      mReflowId = gReflowInx;             \
+      gReflowControlCnt[mReflowId] = 0;   \
+      gReflowControlCntRQ[mReflowId] = 0; \
+    } else {                              \
+      mReflowId = -1;                     \
+    }
+
+// reflow messages
+#  define REFLOW_DEBUG_MSG(_msg1) printf((_msg1))
+#  define REFLOW_DEBUG_MSG2(_msg1, _msg2) printf((_msg1), (_msg2))
+#  define REFLOW_DEBUG_MSG3(_msg1, _msg2, _msg3) \
+    printf((_msg1), (_msg2), (_msg3))
+#  define REFLOW_DEBUG_MSG4(_msg1, _msg2, _msg3, _msg4) \
+    printf((_msg1), (_msg2), (_msg3), (_msg4))
+
+#else  //-------------
+
+#  define REFLOW_COUNTER_REQUEST()
+#  define REFLOW_COUNTER()
+#  define REFLOW_COUNTER_DUMP(__desc)
+#  define REFLOW_COUNTER_INIT()
+
+#  define REFLOW_DEBUG_MSG(_msg)
+#  define REFLOW_DEBUG_MSG2(_msg1, _msg2)
+#  define REFLOW_DEBUG_MSG3(_msg1, _msg2, _msg3)
+#  define REFLOW_DEBUG_MSG4(_msg1, _msg2, _msg3, _msg4)
+
+#endif
+
+//------------------------------------------
+// This is for being VERY noisy
+//------------------------------------------
+#ifdef DO_VERY_NOISY
+#  define REFLOW_NOISY_MSG(_msg1) printf((_msg1))
+#  define REFLOW_NOISY_MSG2(_msg1, _msg2) printf((_msg1), (_msg2))
+#  define REFLOW_NOISY_MSG3(_msg1, _msg2, _msg3) \
+    printf((_msg1), (_msg2), (_msg3))
+#  define REFLOW_NOISY_MSG4(_msg1, _msg2, _msg3, _msg4) \
+    printf((_msg1), (_msg2), (_msg3), (_msg4))
+#else
+#  define REFLOW_NOISY_MSG(_msg)
+#  define REFLOW_NOISY_MSG2(_msg1, _msg2)
+#  define REFLOW_NOISY_MSG3(_msg1, _msg2, _msg3)
+#  define REFLOW_NOISY_MSG4(_msg1, _msg2, _msg3, _msg4)
+#endif
+
+//------------------------------------------
+// Displays value in pixels or twips
+//------------------------------------------
+#ifdef DO_PIXELS
+#  define PX(__v) __v / 15
+#else
+#  define PX(__v) __v
+#endif
+
+//------------------------------------------------------
+//-- Done with macros
+//------------------------------------------------------
+
+nsComboboxControlFrame::nsComboboxControlFrame(ComputedStyle* aStyle,
+                                               nsPresContext* aPresContext)
+    : nsBlockFrame(aStyle, aPresContext, kClassID),
+      mDisplayFrame(nullptr),
+      mButtonFrame(nullptr),
+      mDisplayISize(0),
+      mMaxDisplayISize(0),
+      mRecentSelectedIndex(NS_SKIP_NOTIFY_INDEX),
+      mDisplayedIndex(-1),
+      mInRedisplayText(false),
+      mIsOpenInParentProcess(false){REFLOW_COUNTER_INIT()}
+
+      //--------------------------------------------------------------
+      nsComboboxControlFrame::~nsComboboxControlFrame() {
+  REFLOW_COUNTER_DUMP("nsCCF");
+}
+
+//--------------------------------------------------------------
+
+NS_QUERYFRAME_HEAD(nsComboboxControlFrame)
+  NS_QUERYFRAME_ENTRY(nsComboboxControlFrame)
+  NS_QUERYFRAME_ENTRY(nsIFormControlFrame)
+  NS_QUERYFRAME_ENTRY(nsIAnonymousContentCreator)
+  NS_QUERYFRAME_ENTRY(nsISelectControlFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsBlockFrame)
+
+#ifdef ACCESSIBILITY
+a11y::AccType nsComboboxControlFrame::AccessibleType() {
+  return a11y::eHTMLComboboxType;
+}
+#endif
+
+void nsComboboxControlFrame::SetFocus(bool aOn, bool aRepaint) {
+  // This is needed on a temporary basis. It causes the focus
+  // rect to be drawn. This is much faster than ReResolvingStyle
+  // Bug 32920
+  InvalidateFrame();
+}
+
+nsPoint nsComboboxControlFrame::GetCSSTransformTranslation() {
+  nsIFrame* frame = this;
+  bool is3DTransform = false;
+  Matrix transform;
+  while (frame) {
+    nsIFrame* parent;
+    Matrix4x4Flagged ctm = frame->GetTransformMatrix(
+        ViewportType::Layout, RelativeTo{nullptr}, &parent);
+    Matrix matrix;
+    if (ctm.Is2D(&matrix)) {
+      transform = transform * matrix;
+    } else {
+      is3DTransform = true;
+      break;
+    }
+    frame = parent;
+  }
+  nsPoint translation;
+  if (!is3DTransform && !transform.HasNonTranslation()) {
+    nsPresContext* pc = PresContext();
+    // To get the translation introduced only by transforms we subtract the
+    // regular non-transform translation.
+    nsRootPresContext* rootPC = pc->GetRootPresContext();
+    if (rootPC) {
+      int32_t apd = pc->AppUnitsPerDevPixel();
+      translation.x = NSFloatPixelsToAppUnits(transform._31, apd);
+      translation.y = NSFloatPixelsToAppUnits(transform._32, apd);
+      translation -= GetOffsetToCrossDoc(rootPC->PresShell()->GetRootFrame());
+    }
+  }
+  return translation;
+}
+
+//----------------------------------------------------------
+//
+//----------------------------------------------------------
+#ifdef DO_REFLOW_DEBUG
+static int myCounter = 0;
+
+static void printSize(char* aDesc, nscoord aSize) {
+  printf(" %s: ", aDesc);
+  if (aSize == NS_UNCONSTRAINEDSIZE) {
+    printf("UC");
+  } else {
+    printf("%d", PX(aSize));
+  }
+}
+#endif
+
+//-------------------------------------------------------------------
+//-- Main Reflow for the Combobox
+//-------------------------------------------------------------------
+
+bool nsComboboxControlFrame::HasDropDownButton() const {
+  const nsStyleDisplay* disp = StyleDisplay();
+  // FIXME(emilio): Blink also shows this for menulist-button and such... Seems
+  // more similar to our mac / linux implementation.
+  return disp->EffectiveAppearance() == StyleAppearance::Menulist &&
+         (!IsThemed(disp) ||
+          PresContext()->Theme()->ThemeNeedsComboboxDropmarker());
+}
+
+nscoord nsComboboxControlFrame::DropDownButtonISize() {
+  if (!HasDropDownButton()) {
+    return 0;
+  }
+
+  nsPresContext* pc = PresContext();
+  LayoutDeviceIntSize dropdownButtonSize = pc->Theme()->GetMinimumWidgetSize(
+      pc, this, StyleAppearance::MozMenulistArrowButton);
+  return pc->DevPixelsToAppUnits(dropdownButtonSize.width);
+}
+
+int32_t nsComboboxControlFrame::CharCountOfLargestOptionForInflation() const {
+  uint32_t maxLength = 0;
+  nsAutoString label;
+  for (auto i : IntegerRange(Select().Options()->Length())) {
+    GetOptionText(i, label);
+    maxLength = std::max(
+        maxLength,
+        nsTextFrameUtils::ComputeApproximateLengthWithWhitespaceCompression(
+            label, StyleText()));
+  }
+  if (MOZ_UNLIKELY(maxLength > uint32_t(INT32_MAX))) {
+    return INT32_MAX;
+  }
+  return int32_t(maxLength);
+}
+
+nscoord nsComboboxControlFrame::GetLongestOptionISize(
+    gfxContext* aRenderingContext) const {
+  // Compute the width of each option's (potentially text-transformed) text,
+  // and use the widest one as part of our intrinsic size.
+  nscoord maxOptionSize = 0;
+  nsAutoString label;
+  nsAutoString transformedLabel;
+  RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
+  const nsStyleText* textStyle = StyleText();
+  auto textTransform = textStyle->mTextTransform.IsNone()
+                           ? Nothing()
+                           : Some(textStyle->mTextTransform);
+  nsAtom* language = StyleFont()->mLanguage;
+  AutoTArray<bool, 50> charsToMergeArray;
+  AutoTArray<bool, 50> deletedCharsArray;
+  for (auto i : IntegerRange(Select().Options()->Length())) {
+    GetOptionText(i, label);
+    const nsAutoString* stringToUse = &label;
+    if (textTransform ||
+        textStyle->mWebkitTextSecurity != StyleTextSecurity::None) {
+      transformedLabel.Truncate();
+      charsToMergeArray.SetLengthAndRetainStorage(0);
+      deletedCharsArray.SetLengthAndRetainStorage(0);
+      nsCaseTransformTextRunFactory::TransformString(
+          label, transformedLabel, textTransform,
+          textStyle->TextSecurityMaskChar(),
+          /* aCaseTransformsOnly = */ false, language, charsToMergeArray,
+          deletedCharsArray);
+      stringToUse = &transformedLabel;
+    }
+    maxOptionSize = std::max(maxOptionSize,
+                             nsLayoutUtils::AppUnitWidthOfStringBidi(
+                                 *stringToUse, this, *fm, *aRenderingContext));
+  }
+  if (maxOptionSize) {
+    // HACK: Add one app unit to workaround silly Netgear router styling, see
+    // bug 1769580. In practice since this comes from font metrics is unlikely
+    // to be perceivable.
+    maxOptionSize += 1;
+  }
+  return maxOptionSize;
+}
+
+nscoord nsComboboxControlFrame::GetIntrinsicISize(gfxContext* aRenderingContext,
+                                                  IntrinsicISizeType aType) {
+  Maybe<nscoord> containISize = ContainIntrinsicISize(NS_UNCONSTRAINEDSIZE);
+  if (containISize && *containISize != NS_UNCONSTRAINEDSIZE) {
+    return *containISize;
+  }
+
+  nscoord displayISize = mDisplayFrame->IntrinsicISizeOffsets().padding;
+  if (!containISize && !StyleContent()->mContent.IsNone()) {
+    displayISize += GetLongestOptionISize(aRenderingContext);
+  }
+
+  // Add room for the dropmarker button (if there is one).
+  displayISize += DropDownButtonISize();
+  return displayISize;
+}
+
+nscoord nsComboboxControlFrame::GetMinISize(gfxContext* aRenderingContext) {
+  nscoord minISize;
+  DISPLAY_MIN_INLINE_SIZE(this, minISize);
+  minISize = GetIntrinsicISize(aRenderingContext, IntrinsicISizeType::MinISize);
+  return minISize;
+}
+
+nscoord nsComboboxControlFrame::GetPrefISize(gfxContext* aRenderingContext) {
+  nscoord prefISize;
+  DISPLAY_PREF_INLINE_SIZE(this, prefISize);
+  prefISize =
+      GetIntrinsicISize(aRenderingContext, IntrinsicISizeType::PrefISize);
+  return prefISize;
+}
+
+dom::HTMLSelectElement& nsComboboxControlFrame::Select() const {
+  return *static_cast<dom::HTMLSelectElement*>(GetContent());
+}
+
+void nsComboboxControlFrame::GetOptionText(uint32_t aIndex,
+                                           nsAString& aText) const {
+  aText.Truncate();
+  if (Element* el = Select().Options()->GetElementAt(aIndex)) {
+    static_cast<dom::HTMLOptionElement*>(el)->GetRenderedLabel(aText);
+  }
+}
+
+void nsComboboxControlFrame::Reflow(nsPresContext* aPresContext,
+                                    ReflowOutput& aDesiredSize,
+                                    const ReflowInput& aReflowInput,
+                                    nsReflowStatus& aStatus) {
+  MarkInReflow();
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+  // Constraints we try to satisfy:
+
+  // 1) Default inline size of button is the vertical scrollbar size
+  // 2) If the inline size of button is bigger than our inline size, set
+  //    inline size of button to 0.
+  // 3) Default block size of button is block size of display area
+  // 4) Inline size of display area is whatever is left over from our
+  //    inline size after allocating inline size for the button.
+
+  if (!mDisplayFrame) {
+    NS_ERROR("Why did the frame constructor allow this to happen?  Fix it!!");
+    return;
+  }
+
+  // Make sure the displayed text is the same as the selected option,
+  // bug 297389.
+  mDisplayedIndex = Select().SelectedIndex();
+
+  // In dropped down mode the "selected index" is the hovered menu item,
+  // we want the last selected item which is |mDisplayedIndex| in this case.
+  RedisplayText();
+
+  WritingMode wm = aReflowInput.GetWritingMode();
+
+  // Check if the theme specifies a minimum size for the dropdown button
+  // first.
+  const nscoord buttonISize = DropDownButtonISize();
+  const auto borderPadding = aReflowInput.ComputedLogicalBorderPadding(wm);
+  const auto padding = aReflowInput.ComputedLogicalPadding(wm);
+  const auto border = borderPadding - padding;
+
+  mDisplayISize = aReflowInput.ComputedISize() - buttonISize;
+  mMaxDisplayISize = mDisplayISize + padding.IEnd(wm);
+
+  nsBlockFrame::Reflow(aPresContext, aDesiredSize, aReflowInput, aStatus);
+
+  // The button should occupy the same space as a scrollbar, and its position
+  // starts from the border edge.
+  if (mButtonFrame) {
+    LogicalRect buttonRect(wm);
+    buttonRect.IStart(wm) = borderPadding.IStart(wm) + mMaxDisplayISize;
+    buttonRect.BStart(wm) = border.BStart(wm);
+
+    buttonRect.ISize(wm) = buttonISize;
+    buttonRect.BSize(wm) = mDisplayFrame->BSize(wm) + padding.BStartEnd(wm);
+
+    const nsSize containerSize = aDesiredSize.PhysicalSize();
+    mButtonFrame->SetRect(buttonRect, containerSize);
+  }
+
+  if (!aStatus.IsInlineBreakBefore() && !aStatus.IsFullyComplete()) {
+    // This frame didn't fit inside a fragmentation container.  Splitting
+    // a nsComboboxControlFrame makes no sense, so we override the status here.
+    aStatus.Reset();
+  }
+}
+
+void nsComboboxControlFrame::Init(nsIContent* aContent,
+                                  nsContainerFrame* aParent,
+                                  nsIFrame* aPrevInFlow) {
+  nsBlockFrame::Init(aContent, aParent, aPrevInFlow);
+
+  mEventListener = new HTMLSelectEventListener(
+      Select(), HTMLSelectEventListener::SelectType::Combobox);
+}
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult nsComboboxControlFrame::GetFrameName(nsAString& aResult) const {
+  return MakeFrameName(u"ComboboxControl"_ns, aResult);
+}
+#endif
+
+///////////////////////////////////////////////////////////////
+
+nsresult nsComboboxControlFrame::RedisplaySelectedText() {
+  nsAutoScriptBlocker scriptBlocker;
+  mDisplayedIndex = Select().SelectedIndex();
+  return RedisplayText();
+}
+
+nsresult nsComboboxControlFrame::RedisplayText() {
+  nsString previewValue;
+  nsString previousText(mDisplayedOptionTextOrPreview);
+
+  Select().GetPreviewValue(previewValue);
+  // Get the text to display
+  if (!previewValue.IsEmpty()) {
+    mDisplayedOptionTextOrPreview = previewValue;
+  } else if (mDisplayedIndex != -1 && !StyleContent()->mContent.IsNone()) {
+    GetOptionText(mDisplayedIndex, mDisplayedOptionTextOrPreview);
+  } else {
+    mDisplayedOptionTextOrPreview.Truncate();
+  }
+
+  REFLOW_DEBUG_MSG2(
+      "RedisplayText \"%s\"\n",
+      NS_LossyConvertUTF16toASCII(mDisplayedOptionTextOrPreview).get());
+
+  // Send reflow command because the new text maybe larger
+  nsresult rv = NS_OK;
+  if (mDisplayContent && !previousText.Equals(mDisplayedOptionTextOrPreview)) {
+    // Don't call ActuallyDisplayText(true) directly here since that
+    // could cause recursive frame construction. See bug 283117 and the comment
+    // in HandleRedisplayTextEvent() below.
+
+    // Revoke outstanding events to avoid out-of-order events which could mean
+    // displaying the wrong text.
+    mRedisplayTextEvent.Revoke();
+
+    NS_ASSERTION(!nsContentUtils::IsSafeToRunScript(),
+                 "If we happen to run our redisplay event now, we might kill "
+                 "ourselves!");
+
+    mRedisplayTextEvent = new RedisplayTextEvent(this);
+    nsContentUtils::AddScriptRunner(mRedisplayTextEvent.get());
+  }
+  return rv;
+}
+
+void nsComboboxControlFrame::HandleRedisplayTextEvent() {
+  // First, make sure that the content model is up to date and we've
+  // constructed the frames for all our content in the right places.
+  // Otherwise they'll end up under the wrong insertion frame when we
+  // ActuallyDisplayText, since that flushes out the content sink by
+  // calling SetText on a DOM node with aNotify set to true.  See bug
+  // 289730.
+  AutoWeakFrame weakThis(this);
+  PresContext()->Document()->FlushPendingNotifications(
+      FlushType::ContentAndNotify);
+  if (!weakThis.IsAlive()) return;
+
+  // Redirect frame insertions during this method (see
+  // GetContentInsertionFrame()) so that any reframing that the frame
+  // constructor forces upon us is inserted into the correct parent
+  // (mDisplayFrame). See bug 282607.
+  MOZ_ASSERT(!mInRedisplayText, "Nested RedisplayText");
+  mInRedisplayText = true;
+  mRedisplayTextEvent.Forget();
+
+  ActuallyDisplayText(true);
+  if (!weakThis.IsAlive()) {
+    return;
+  }
+
+  // XXXbz This should perhaps be IntrinsicDirty::None. Check.
+  PresShell()->FrameNeedsReflow(mDisplayFrame,
+                                IntrinsicDirty::FrameAncestorsAndDescendants,
+                                NS_FRAME_IS_DIRTY);
+
+  mInRedisplayText = false;
+}
+
+void nsComboboxControlFrame::ActuallyDisplayText(bool aNotify) {
+  RefPtr<nsTextNode> displayContent = mDisplayContent;
+  if (mDisplayedOptionTextOrPreview.IsEmpty()) {
+    // Have to use a space character of some sort for line-block-size
+    // calculations to be right. Also, the space character must be zero-width
+    // in order for the the inline-size calculations to be consistent between
+    // size-contained comboboxes vs. empty comboboxes.
+    //
+    // XXXdholbert Does this space need to be "non-breaking"? I'm not sure
+    // if it matters, but we previously had a comment here (added in 2002)
+    // saying "Have to use a non-breaking space for line-height calculations
+    // to be right". So I'll stick with a non-breaking space for now...
+    static const char16_t space = 0xFEFF;
+    displayContent->SetText(&space, 1, aNotify);
+  } else {
+    displayContent->SetText(mDisplayedOptionTextOrPreview, aNotify);
+  }
+}
+
+int32_t nsComboboxControlFrame::GetIndexOfDisplayArea() {
+  return mDisplayedIndex;
+}
+
+bool nsComboboxControlFrame::IsDroppedDown() const {
+  return Select().OpenInParentProcess();
+}
+
+//----------------------------------------------------------------------
+// nsISelectControlFrame
+//----------------------------------------------------------------------
+NS_IMETHODIMP
+nsComboboxControlFrame::DoneAddingChildren(bool aIsDone) { return NS_OK; }
+
+NS_IMETHODIMP
+nsComboboxControlFrame::AddOption(int32_t aIndex) {
+  if (aIndex <= mDisplayedIndex) {
+    ++mDisplayedIndex;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsComboboxControlFrame::RemoveOption(int32_t aIndex) {
+  if (Select().Options()->Length()) {
+    if (aIndex < mDisplayedIndex) {
+      --mDisplayedIndex;
+    } else if (aIndex == mDisplayedIndex) {
+      mDisplayedIndex = 0;  // IE6 compat
+      RedisplayText();
+    }
+  } else {
+    // If we removed the last option, we need to blank things out
+    mDisplayedIndex = -1;
+    RedisplayText();
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP_(void)
+nsComboboxControlFrame::OnSetSelectedIndex(int32_t aOldIndex,
+                                           int32_t aNewIndex) {
+  nsAutoScriptBlocker scriptBlocker;
+  mDisplayedIndex = aNewIndex;
+  RedisplayText();
+}
+
+// End nsISelectControlFrame
+//----------------------------------------------------------------------
+
+nsresult nsComboboxControlFrame::HandleEvent(nsPresContext* aPresContext,
+                                             WidgetGUIEvent* aEvent,
+                                             nsEventStatus* aEventStatus) {
+  NS_ENSURE_ARG_POINTER(aEventStatus);
+
+  if (nsEventStatus_eConsumeNoDefault == *aEventStatus) {
+    return NS_OK;
+  }
+
+  if (mContent->AsElement()->State().HasState(dom::ElementState::DISABLED)) {
+    return NS_OK;
+  }
+
+  // If we have style that affects how we are selected, feed event down to
+  // nsIFrame::HandleEvent so that selection takes place when appropriate.
+  if (IsContentDisabled()) {
+    return nsBlockFrame::HandleEvent(aPresContext, aEvent, aEventStatus);
+  }
+  return NS_OK;
+}
+
+nsContainerFrame* nsComboboxControlFrame::GetContentInsertionFrame() {
+  return mInRedisplayText ? mDisplayFrame : nullptr;
+}
+
+void nsComboboxControlFrame::AppendDirectlyOwnedAnonBoxes(
+    nsTArray<OwnedAnonBox>& aResult) {
+  aResult.AppendElement(OwnedAnonBox(mDisplayFrame));
+}
+
+nsresult nsComboboxControlFrame::CreateAnonymousContent(
+    nsTArray<ContentInfo>& aElements) {
+  // The frames used to display the combo box and the button used to popup the
+  // dropdown list are created through anonymous content. The dropdown list is
+  // not created through anonymous content because its frame is initialized
+  // specifically for the drop-down case and it is placed a special list
+  // referenced through NS_COMBO_FRAME_POPUP_LIST_INDEX to keep separate from
+  // the layout of the display and button.
+  //
+  // Note: The value attribute of the display content is set when an item is
+  // selected in the dropdown list. If the content specified below does not
+  // honor the value attribute than nothing will be displayed.
+
+  // For now the content that is created corresponds to two input buttons. It
+  // would be better to create the tag as something other than input, but then
+  // there isn't any way to create a button frame since it isn't possible to set
+  // the display type in CSS2 to create a button frame.
+
+  // create content used for display
+  // nsAtom* tag = NS_Atomize("mozcombodisplay");
+
+  // Add a child text content node for the label
+
+  nsNodeInfoManager* nimgr = mContent->NodeInfo()->NodeInfoManager();
+
+  mDisplayContent = new (nimgr) nsTextNode(nimgr);
+
+  // set the value of the text node
+  mDisplayedIndex = Select().SelectedIndex();
+  if (mDisplayedIndex != -1) {
+    GetOptionText(mDisplayedIndex, mDisplayedOptionTextOrPreview);
+  }
+  ActuallyDisplayText(false);
+
+  aElements.AppendElement(mDisplayContent);
+  if (HasDropDownButton()) {
+    mButtonContent = mContent->OwnerDoc()->CreateHTMLElement(nsGkAtoms::button);
+    if (!mButtonContent) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    // make someone to listen to the button.
+    mButtonContent->SetAttr(kNameSpaceID_None, nsGkAtoms::type, u"button"_ns,
+                            false);
+    // Set tabindex="-1" so that the button is not tabbable
+    mButtonContent->SetAttr(kNameSpaceID_None, nsGkAtoms::tabindex, u"-1"_ns,
+                            false);
+    aElements.AppendElement(mButtonContent);
+  }
+
+  return NS_OK;
+}
+
+void nsComboboxControlFrame::AppendAnonymousContentTo(
+    nsTArray<nsIContent*>& aElements, uint32_t aFilter) {
+  if (mDisplayContent) {
+    aElements.AppendElement(mDisplayContent);
+  }
+
+  if (mButtonContent) {
+    aElements.AppendElement(mButtonContent);
+  }
+}
+
+nsIContent* nsComboboxControlFrame::GetDisplayNode() const {
+  return mDisplayContent;
+}
+
+// XXXbz this is a for-now hack.  Now that display:inline-block works,
+// need to revisit this.
+class nsComboboxDisplayFrame final : public nsBlockFrame {
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(nsComboboxDisplayFrame)
+
+  nsComboboxDisplayFrame(ComputedStyle* aStyle,
+                         nsComboboxControlFrame* aComboBox)
+      : nsBlockFrame(aStyle, aComboBox->PresContext(), kClassID),
+        mComboBox(aComboBox) {}
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const final {
+    return MakeFrameName(u"ComboboxDisplay"_ns, aResult);
+  }
+#endif
+
+  void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
+              const ReflowInput& aReflowInput, nsReflowStatus& aStatus) final;
+
+  void BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                        const nsDisplayListSet& aLists) final;
+
+ protected:
+  nsComboboxControlFrame* mComboBox;
+};
+
+NS_IMPL_FRAMEARENA_HELPERS(nsComboboxDisplayFrame)
+
+void nsComboboxDisplayFrame::Reflow(nsPresContext* aPresContext,
+                                    ReflowOutput& aDesiredSize,
+                                    const ReflowInput& aReflowInput,
+                                    nsReflowStatus& aStatus) {
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+  MOZ_ASSERT(aReflowInput.mParentReflowInput &&
+                 aReflowInput.mParentReflowInput->mFrame == mComboBox,
+             "Combobox's frame tree is wrong!");
+
+  ReflowInput state(aReflowInput);
+  if (state.ComputedBSize() == NS_UNCONSTRAINEDSIZE) {
+    state.SetLineHeight(state.mParentReflowInput->GetLineHeight());
+  }
+  const WritingMode wm = aReflowInput.GetWritingMode();
+  const LogicalMargin bp = state.ComputedLogicalBorderPadding(wm);
+  MOZ_ASSERT(bp.BStartEnd(wm) == 0,
+             "We shouldn't have border and padding in the block axis in UA!");
+  nscoord inlineBp = bp.IStartEnd(wm);
+  nscoord computedISize = mComboBox->mDisplayISize - inlineBp;
+
+  // Other UAs ignore padding in some (but not all) platforms for (themed only)
+  // comboboxes. Instead of doing that, we prevent that padding if present from
+  // clipping the display text, by enforcing the display text minimum size in
+  // that situation.
+  const bool shouldHonorMinISize =
+      mComboBox->StyleDisplay()->EffectiveAppearance() ==
+      StyleAppearance::Menulist;
+  if (shouldHonorMinISize) {
+    computedISize = std::max(state.ComputedMinISize(), computedISize);
+    // Don't let this size go over mMaxDisplayISize, since that'd be
+    // observable via clientWidth / scrollWidth.
+    computedISize =
+        std::min(computedISize, mComboBox->mMaxDisplayISize - inlineBp);
+  }
+
+  state.SetComputedISize(std::max(0, computedISize));
+  nsBlockFrame::Reflow(aPresContext, aDesiredSize, state, aStatus);
+  aStatus.Reset();  // this type of frame can't be split
+}
+
+void nsComboboxDisplayFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                                              const nsDisplayListSet& aLists) {
+  nsDisplayListCollection set(aBuilder);
+  nsBlockFrame::BuildDisplayList(aBuilder, set);
+
+  // remove background items if parent frame is themed
+  if (mComboBox->IsThemed()) {
+    set.BorderBackground()->DeleteAll(aBuilder);
+  }
+
+  set.MoveTo(aLists);
+}
+
+nsIFrame* nsComboboxControlFrame::CreateFrameForDisplayNode() {
+  MOZ_ASSERT(mDisplayContent);
+
+  // Get PresShell
+  mozilla::PresShell* ps = PresShell();
+  ServoStyleSet* styleSet = ps->StyleSet();
+
+  // create the ComputedStyle for the anonymous block frame and text frame
+  RefPtr<ComputedStyle> computedStyle =
+      styleSet->ResolveInheritingAnonymousBoxStyle(
+          PseudoStyleType::mozDisplayComboboxControlFrame, mComputedStyle);
+
+  RefPtr<ComputedStyle> textComputedStyle =
+      styleSet->ResolveStyleForText(mDisplayContent, mComputedStyle);
+
+  // Start by creating our anonymous block frame
+  mDisplayFrame = new (ps) nsComboboxDisplayFrame(computedStyle, this);
+  mDisplayFrame->Init(mContent, this, nullptr);
+
+  // Create a text frame and put it inside the block frame
+  nsIFrame* textFrame = NS_NewTextFrame(ps, textComputedStyle);
+
+  // initialize the text frame
+  textFrame->Init(mDisplayContent, mDisplayFrame, nullptr);
+  mDisplayContent->SetPrimaryFrame(textFrame);
+
+  mDisplayFrame->SetInitialChildList(FrameChildListID::Principal,
+                                     nsFrameList(textFrame, textFrame));
+  return mDisplayFrame;
+}
+
+void nsComboboxControlFrame::Destroy(DestroyContext& aContext) {
+  // Revoke any pending RedisplayTextEvent
+  mRedisplayTextEvent.Revoke();
+
+  mEventListener->Detach();
+
+  // Cleanup frames in popup child list
+  aContext.AddAnonymousContent(mDisplayContent.forget());
+  aContext.AddAnonymousContent(mButtonContent.forget());
+  nsBlockFrame::Destroy(aContext);
+}
+
+const nsFrameList& nsComboboxControlFrame::GetChildList(
+    ChildListID aListID) const {
+  return nsBlockFrame::GetChildList(aListID);
+}
+
+void nsComboboxControlFrame::GetChildLists(nsTArray<ChildList>* aLists) const {
+  nsBlockFrame::GetChildLists(aLists);
+}
+
+void nsComboboxControlFrame::SetInitialChildList(ChildListID aListID,
+                                                 nsFrameList&& aChildList) {
+  for (nsIFrame* f : aChildList) {
+    MOZ_ASSERT(f->GetParent() == this, "Unexpected parent");
+    nsCOMPtr<nsIFormControl> formControl = do_QueryInterface(f->GetContent());
+    if (formControl &&
+        formControl->ControlType() == FormControlType::ButtonButton) {
+      mButtonFrame = f;
+      break;
+    }
+  }
+  nsBlockFrame::SetInitialChildList(aListID, std::move(aChildList));
+}
+
+namespace mozilla {
+
+class nsDisplayComboboxFocus : public nsPaintedDisplayItem {
+ public:
+  nsDisplayComboboxFocus(nsDisplayListBuilder* aBuilder,
+                         nsComboboxControlFrame* aFrame)
+      : nsPaintedDisplayItem(aBuilder, aFrame) {
+    MOZ_COUNT_CTOR(nsDisplayComboboxFocus);
+  }
+  MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayComboboxFocus)
+
+  void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
+  NS_DISPLAY_DECL_NAME("ComboboxFocus", TYPE_COMBOBOX_FOCUS)
+};
+
+void nsDisplayComboboxFocus::Paint(nsDisplayListBuilder* aBuilder,
+                                   gfxContext* aCtx) {
+  static_cast<nsComboboxControlFrame*>(mFrame)->PaintFocus(
+      *aCtx->GetDrawTarget(), ToReferenceFrame());
+}
+
+}  // namespace mozilla
+
+void nsComboboxControlFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                                              const nsDisplayListSet& aLists) {
+  if (aBuilder->IsForEventDelivery()) {
+    // Don't allow children to receive events.
+    // REVIEW: following old GetFrameForPoint
+    DisplayBorderBackgroundOutline(aBuilder, aLists);
+  } else {
+    // REVIEW: Our in-flow child frames are inline-level so they will paint in
+    // our content list, so we don't need to mess with layers.
+    nsBlockFrame::BuildDisplayList(aBuilder, aLists);
+  }
+
+  // draw a focus indicator only when focus rings should be drawn
+  if (Select().State().HasState(dom::ElementState::FOCUSRING) && IsThemed() &&
+      PresContext()->Theme()->ThemeWantsButtonInnerFocusRing()) {
+    aLists.Content()->AppendNewToTop<nsDisplayComboboxFocus>(aBuilder, this);
+  }
+
+  DisplaySelectionOverlay(aBuilder, aLists.Content());
+}
+
+void nsComboboxControlFrame::PaintFocus(DrawTarget& aDrawTarget, nsPoint aPt) {
+  /* Do we need to do anything? */
+  dom::ElementState state = mContent->AsElement()->State();
+  if (state.HasState(dom::ElementState::DISABLED) ||
+      !state.HasState(dom::ElementState::FOCUS)) {
+    return;
+  }
+
+  int32_t appUnitsPerDevPixel = PresContext()->AppUnitsPerDevPixel();
+
+  nsRect clipRect = mDisplayFrame->GetRect() + aPt;
+  aDrawTarget.PushClipRect(
+      NSRectToSnappedRect(clipRect, appUnitsPerDevPixel, aDrawTarget));
+
+  StrokeOptions strokeOptions;
+  nsLayoutUtils::InitDashPattern(strokeOptions, StyleBorderStyle::Dotted);
+  ColorPattern color(ToDeviceColor(StyleText()->mColor));
+  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
+  clipRect.width -= onePixel;
+  clipRect.height -= onePixel;
+  Rect r = ToRect(nsLayoutUtils::RectToGfxRect(clipRect, appUnitsPerDevPixel));
+  StrokeSnappedEdgesOfRect(r, aDrawTarget, color, strokeOptions);
+
+  aDrawTarget.PopClip();
+}
+
+//---------------------------------------------------------
+// gets the content (an option) by index and then set it as
+// being selected or not selected
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsComboboxControlFrame::OnOptionSelected(int32_t aIndex, bool aSelected) {
+  if (aSelected) {
+    nsAutoScriptBlocker blocker;
+    mDisplayedIndex = aIndex;
+    RedisplayText();
+  } else {
+    AutoWeakFrame weakFrame(this);
+    RedisplaySelectedText();
+    if (weakFrame.IsAlive()) {
+      FireValueChangeEvent();  // Fire after old option is unselected
+    }
+  }
+  return NS_OK;
+}
+
+void nsComboboxControlFrame::FireValueChangeEvent() {
+  // Fire ValueChange event to indicate data value of combo box has changed
+  nsContentUtils::AddScriptRunner(new AsyncEventDispatcher(
+      mContent, u"ValueChange"_ns, CanBubble::eYes, ChromeOnlyDispatch::eNo));
+}