1 files changed, 528 insertions, 0 deletions
diff --git a/layout/forms/nsButtonFrameRenderer.cpp b/layout/forms/nsButtonFrameRenderer.cpp
new file mode 100644
index 0000000000..647c2c0dd9
--- /dev/null
+++ b/layout/forms/nsButtonFrameRenderer.cpp
@@ -0,0 +1,528 @@
+/* -*- 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 "nsButtonFrameRenderer.h"
+#include "nsCSSRendering.h"
+#include "nsPresContext.h"
+#include "nsPresContextInlines.h"
+#include "nsGkAtoms.h"
+#include "nsCSSPseudoElements.h"
+#include "nsNameSpaceManager.h"
+#include "mozilla/ServoStyleSet.h"
+#include "mozilla/Unused.h"
+#include "nsDisplayList.h"
+#include "nsITheme.h"
+#include "nsIFrame.h"
+#include "mozilla/EventStates.h"
+#include "mozilla/dom/Element.h"
+#include "Layers.h"
+
+#include "gfxUtils.h"
+#include "mozilla/layers/RenderRootStateManager.h"
+
+#define ACTIVE "active"
+#define HOVER "hover"
+#define FOCUS "focus"
+
+using namespace mozilla;
+using namespace mozilla::image;
+using namespace mozilla::layers;
+
+nsButtonFrameRenderer::nsButtonFrameRenderer() : mFrame(nullptr) {
+  MOZ_COUNT_CTOR(nsButtonFrameRenderer);
+}
+
+nsButtonFrameRenderer::~nsButtonFrameRenderer() {
+  MOZ_COUNT_DTOR(nsButtonFrameRenderer);
+}
+
+void nsButtonFrameRenderer::SetFrame(nsIFrame* aFrame,
+                                     nsPresContext* aPresContext) {
+  mFrame = aFrame;
+  ReResolveStyles(aPresContext);
+}
+
+nsIFrame* nsButtonFrameRenderer::GetFrame() { return mFrame; }
+
+void nsButtonFrameRenderer::SetDisabled(bool aDisabled, bool aNotify) {
+  dom::Element* element = mFrame->GetContent()->AsElement();
+  if (aDisabled)
+    element->SetAttr(kNameSpaceID_None, nsGkAtoms::disabled, u""_ns, aNotify);
+  else
+    element->UnsetAttr(kNameSpaceID_None, nsGkAtoms::disabled, aNotify);
+}
+
+bool nsButtonFrameRenderer::isDisabled() {
+  return mFrame->GetContent()->AsElement()->IsDisabled();
+}
+
+class nsDisplayButtonBoxShadowOuter : public nsPaintedDisplayItem {
+ public:
+  nsDisplayButtonBoxShadowOuter(nsDisplayListBuilder* aBuilder,
+                                nsIFrame* aFrame)
+      : nsPaintedDisplayItem(aBuilder, aFrame) {
+    MOZ_COUNT_CTOR(nsDisplayButtonBoxShadowOuter);
+  }
+  MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayButtonBoxShadowOuter)
+
+  virtual bool CreateWebRenderCommands(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager,
+      nsDisplayListBuilder* aDisplayListBuilder) override;
+
+  bool CanBuildWebRenderDisplayItems();
+
+  virtual void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
+  virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
+                           bool* aSnap) const override;
+  NS_DISPLAY_DECL_NAME("ButtonBoxShadowOuter", TYPE_BUTTON_BOX_SHADOW_OUTER)
+};
+
+nsRect nsDisplayButtonBoxShadowOuter::GetBounds(nsDisplayListBuilder* aBuilder,
+                                                bool* aSnap) const {
+  *aSnap = false;
+  return mFrame->InkOverflowRectRelativeToSelf() + ToReferenceFrame();
+}
+
+void nsDisplayButtonBoxShadowOuter::Paint(nsDisplayListBuilder* aBuilder,
+                                          gfxContext* aCtx) {
+  nsRect frameRect = nsRect(ToReferenceFrame(), mFrame->GetSize());
+
+  nsCSSRendering::PaintBoxShadowOuter(mFrame->PresContext(), *aCtx, mFrame,
+                                      frameRect, GetPaintRect());
+}
+
+bool nsDisplayButtonBoxShadowOuter::CanBuildWebRenderDisplayItems() {
+  // FIXME(emilio): Is this right? That doesn't make much sense.
+  if (mFrame->StyleEffects()->mBoxShadow.IsEmpty()) {
+    return false;
+  }
+
+  bool hasBorderRadius;
+  bool nativeTheme =
+      nsCSSRendering::HasBoxShadowNativeTheme(mFrame, hasBorderRadius);
+
+  // We don't support native themed things yet like box shadows around
+  // input buttons.
+  if (nativeTheme) {
+    return false;
+  }
+
+  return true;
+}
+
+bool nsDisplayButtonBoxShadowOuter::CreateWebRenderCommands(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager,
+    nsDisplayListBuilder* aDisplayListBuilder) {
+  if (!CanBuildWebRenderDisplayItems()) {
+    return false;
+  }
+  int32_t appUnitsPerDevPixel = mFrame->PresContext()->AppUnitsPerDevPixel();
+  nsRect shadowRect = nsRect(ToReferenceFrame(), mFrame->GetSize());
+  LayoutDeviceRect deviceBox =
+      LayoutDeviceRect::FromAppUnits(shadowRect, appUnitsPerDevPixel);
+  wr::LayoutRect deviceBoxRect = wr::ToLayoutRect(deviceBox);
+
+  LayoutDeviceRect clipRect =
+      LayoutDeviceRect::FromAppUnits(GetPaintRect(), appUnitsPerDevPixel);
+  wr::LayoutRect deviceClipRect = wr::ToLayoutRect(clipRect);
+
+  bool hasBorderRadius;
+  Unused << nsCSSRendering::HasBoxShadowNativeTheme(mFrame, hasBorderRadius);
+
+  LayoutDeviceSize zeroSize;
+  wr::BorderRadius borderRadius =
+      wr::ToBorderRadius(zeroSize, zeroSize, zeroSize, zeroSize);
+  if (hasBorderRadius) {
+    mozilla::gfx::RectCornerRadii borderRadii;
+    hasBorderRadius = nsCSSRendering::GetBorderRadii(shadowRect, shadowRect,
+                                                     mFrame, borderRadii);
+    if (hasBorderRadius) {
+      borderRadius = wr::ToBorderRadius(
+          LayoutDeviceSize::FromUnknownSize(borderRadii.TopLeft()),
+          LayoutDeviceSize::FromUnknownSize(borderRadii.TopRight()),
+          LayoutDeviceSize::FromUnknownSize(borderRadii.BottomLeft()),
+          LayoutDeviceSize::FromUnknownSize(borderRadii.BottomRight()));
+    }
+  }
+
+  const Span<const StyleBoxShadow> shadows =
+      mFrame->StyleEffects()->mBoxShadow.AsSpan();
+  MOZ_ASSERT(!shadows.IsEmpty());
+
+  for (const StyleBoxShadow& shadow : Reversed(shadows)) {
+    if (shadow.inset) {
+      continue;
+    }
+    float blurRadius =
+        float(shadow.base.blur.ToAppUnits()) / float(appUnitsPerDevPixel);
+    gfx::DeviceColor shadowColor =
+        ToDeviceColor(nsCSSRendering::GetShadowColor(shadow.base, mFrame, 1.0));
+
+    LayoutDevicePoint shadowOffset = LayoutDevicePoint::FromAppUnits(
+        nsPoint(shadow.base.horizontal.ToAppUnits(),
+                shadow.base.vertical.ToAppUnits()),
+        appUnitsPerDevPixel);
+
+    float spreadRadius =
+        float(shadow.spread.ToAppUnits()) / float(appUnitsPerDevPixel);
+
+    aBuilder.PushBoxShadow(deviceBoxRect, deviceClipRect, !BackfaceIsHidden(),
+                           deviceBoxRect, wr::ToLayoutVector2D(shadowOffset),
+                           wr::ToColorF(shadowColor), blurRadius, spreadRadius,
+                           borderRadius, wr::BoxShadowClipMode::Outset);
+  }
+  return true;
+}
+
+class nsDisplayButtonBorder final : public nsPaintedDisplayItem {
+ public:
+  nsDisplayButtonBorder(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
+                        nsButtonFrameRenderer* aRenderer)
+      : nsPaintedDisplayItem(aBuilder, aFrame), mBFR(aRenderer) {
+    MOZ_COUNT_CTOR(nsDisplayButtonBorder);
+  }
+  MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayButtonBorder)
+
+  virtual bool MustPaintOnContentSide() const override { return true; }
+
+  virtual void HitTest(nsDisplayListBuilder* aBuilder, const nsRect& aRect,
+                       HitTestState* aState,
+                       nsTArray<nsIFrame*>* aOutFrames) override {
+    aOutFrames->AppendElement(mFrame);
+  }
+  virtual void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
+  virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
+                           bool* aSnap) const override;
+  virtual nsDisplayItemGeometry* AllocateGeometry(
+      nsDisplayListBuilder* aBuilder) override;
+  virtual void ComputeInvalidationRegion(
+      nsDisplayListBuilder* aBuilder, const nsDisplayItemGeometry* aGeometry,
+      nsRegion* aInvalidRegion) const override;
+  virtual bool CreateWebRenderCommands(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager,
+      nsDisplayListBuilder* aDisplayListBuilder) override;
+  NS_DISPLAY_DECL_NAME("ButtonBorderBackground", TYPE_BUTTON_BORDER_BACKGROUND)
+ private:
+  nsButtonFrameRenderer* mBFR;
+};
+
+nsDisplayItemGeometry* nsDisplayButtonBorder::AllocateGeometry(
+    nsDisplayListBuilder* aBuilder) {
+  return new nsDisplayItemGenericImageGeometry(this, aBuilder);
+}
+
+bool nsDisplayButtonBorder::CreateWebRenderCommands(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager,
+    nsDisplayListBuilder* aDisplayListBuilder) {
+  // This is really a combination of paint box shadow inner +
+  // paint border.
+  aBuilder.StartGroup(this);
+  const nsRect buttonRect = nsRect(ToReferenceFrame(), mFrame->GetSize());
+  bool snap;
+  nsRegion visible = GetBounds(aDisplayListBuilder, &snap);
+  nsDisplayBoxShadowInner::CreateInsetBoxShadowWebRenderCommands(
+      aBuilder, aSc, visible, mFrame, buttonRect);
+
+  bool borderIsEmpty = false;
+  Maybe<nsCSSBorderRenderer> br = nsCSSRendering::CreateBorderRenderer(
+      mFrame->PresContext(), nullptr, mFrame, nsRect(),
+      nsRect(ToReferenceFrame(), mFrame->GetSize()), mFrame->Style(),
+      &borderIsEmpty, mFrame->GetSkipSides());
+  if (!br) {
+    if (borderIsEmpty) {
+      aBuilder.FinishGroup();
+    } else {
+      aBuilder.CancelGroup(true);
+    }
+
+    return borderIsEmpty;
+  }
+
+  br->CreateWebRenderCommands(this, aBuilder, aResources, aSc);
+  aBuilder.FinishGroup();
+  return true;
+}
+
+void nsDisplayButtonBorder::ComputeInvalidationRegion(
+    nsDisplayListBuilder* aBuilder, const nsDisplayItemGeometry* aGeometry,
+    nsRegion* aInvalidRegion) const {
+  auto geometry =
+      static_cast<const nsDisplayItemGenericImageGeometry*>(aGeometry);
+
+  if (aBuilder->ShouldSyncDecodeImages() &&
+      geometry->ShouldInvalidateToSyncDecodeImages()) {
+    bool snap;
+    aInvalidRegion->Or(*aInvalidRegion, GetBounds(aBuilder, &snap));
+  }
+
+  nsDisplayItem::ComputeInvalidationRegion(aBuilder, aGeometry, aInvalidRegion);
+}
+
+void nsDisplayButtonBorder::Paint(nsDisplayListBuilder* aBuilder,
+                                  gfxContext* aCtx) {
+  NS_ASSERTION(mFrame, "No frame?");
+  nsPresContext* pc = mFrame->PresContext();
+  nsRect r = nsRect(ToReferenceFrame(), mFrame->GetSize());
+
+  // draw the border and background inside the focus and outline borders
+  ImgDrawResult result =
+      mBFR->PaintBorder(aBuilder, pc, *aCtx, GetPaintRect(), r);
+
+  nsDisplayItemGenericImageGeometry::UpdateDrawResult(this, result);
+}
+
+nsRect nsDisplayButtonBorder::GetBounds(nsDisplayListBuilder* aBuilder,
+                                        bool* aSnap) const {
+  *aSnap = false;
+  return aBuilder->IsForEventDelivery()
+             ? nsRect(ToReferenceFrame(), mFrame->GetSize())
+             : mFrame->InkOverflowRectRelativeToSelf() + ToReferenceFrame();
+}
+
+class nsDisplayButtonForeground final : public nsPaintedDisplayItem {
+ public:
+  nsDisplayButtonForeground(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
+                            nsButtonFrameRenderer* aRenderer)
+      : nsPaintedDisplayItem(aBuilder, aFrame), mBFR(aRenderer) {
+    MOZ_COUNT_CTOR(nsDisplayButtonForeground);
+  }
+  MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayButtonForeground)
+
+  nsDisplayItemGeometry* AllocateGeometry(
+      nsDisplayListBuilder* aBuilder) override;
+  void ComputeInvalidationRegion(nsDisplayListBuilder* aBuilder,
+                                 const nsDisplayItemGeometry* aGeometry,
+                                 nsRegion* aInvalidRegion) const override;
+  void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
+  bool CreateWebRenderCommands(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager,
+      nsDisplayListBuilder* aDisplayListBuilder) override;
+  NS_DISPLAY_DECL_NAME("ButtonForeground", TYPE_BUTTON_FOREGROUND)
+ private:
+  nsButtonFrameRenderer* mBFR;
+};
+
+nsDisplayItemGeometry* nsDisplayButtonForeground::AllocateGeometry(
+    nsDisplayListBuilder* aBuilder) {
+  return new nsDisplayItemGenericImageGeometry(this, aBuilder);
+}
+
+void nsDisplayButtonForeground::ComputeInvalidationRegion(
+    nsDisplayListBuilder* aBuilder, const nsDisplayItemGeometry* aGeometry,
+    nsRegion* aInvalidRegion) const {
+  auto geometry =
+      static_cast<const nsDisplayItemGenericImageGeometry*>(aGeometry);
+
+  if (aBuilder->ShouldSyncDecodeImages() &&
+      geometry->ShouldInvalidateToSyncDecodeImages()) {
+    bool snap;
+    aInvalidRegion->Or(*aInvalidRegion, GetBounds(aBuilder, &snap));
+  }
+
+  nsDisplayItem::ComputeInvalidationRegion(aBuilder, aGeometry, aInvalidRegion);
+}
+
+void nsDisplayButtonForeground::Paint(nsDisplayListBuilder* aBuilder,
+                                      gfxContext* aCtx) {
+  nsRect r = nsRect(ToReferenceFrame(), mFrame->GetSize());
+
+  // Draw the -moz-focus-inner border
+  ImgDrawResult result = mBFR->PaintInnerFocusBorder(
+      aBuilder, mFrame->PresContext(), *aCtx, GetPaintRect(), r);
+
+  nsDisplayItemGenericImageGeometry::UpdateDrawResult(this, result);
+}
+
+bool nsDisplayButtonForeground::CreateWebRenderCommands(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager,
+    nsDisplayListBuilder* aDisplayListBuilder) {
+  Maybe<nsCSSBorderRenderer> br;
+  bool borderIsEmpty = false;
+  nsRect r = nsRect(ToReferenceFrame(), mFrame->GetSize());
+  br = mBFR->CreateInnerFocusBorderRenderer(aDisplayListBuilder,
+                                            mFrame->PresContext(), nullptr,
+                                            GetPaintRect(), r, &borderIsEmpty);
+
+  if (!br) {
+    return borderIsEmpty;
+  }
+
+  aBuilder.StartGroup(this);
+  br->CreateWebRenderCommands(this, aBuilder, aResources, aSc);
+  aBuilder.FinishGroup();
+
+  return true;
+}
+
+nsresult nsButtonFrameRenderer::DisplayButton(nsDisplayListBuilder* aBuilder,
+                                              nsDisplayList* aBackground,
+                                              nsDisplayList* aForeground) {
+  if (!mFrame->StyleEffects()->mBoxShadow.IsEmpty()) {
+    aBackground->AppendNewToTop<nsDisplayButtonBoxShadowOuter>(aBuilder,
+                                                               GetFrame());
+  }
+
+  nsRect buttonRect =
+      mFrame->GetRectRelativeToSelf() + aBuilder->ToReferenceFrame(mFrame);
+
+  nsDisplayBackgroundImage::AppendBackgroundItemsToTop(aBuilder, mFrame,
+                                                       buttonRect, aBackground);
+
+  aBackground->AppendNewToTop<nsDisplayButtonBorder>(aBuilder, GetFrame(),
+                                                     this);
+
+  // Only display focus rings if we actually have them. Since at most one
+  // button would normally display a focus ring, most buttons won't have them.
+  const auto* disp = mFrame->StyleDisplay();
+  nsPresContext* pc = mFrame->PresContext();
+  if (mInnerFocusStyle && mInnerFocusStyle->StyleBorder()->HasBorder() &&
+      mFrame->IsThemed(disp) &&
+      pc->Theme()->ThemeWantsButtonInnerFocusRing(
+          disp->EffectiveAppearance())) {
+    aForeground->AppendNewToTop<nsDisplayButtonForeground>(aBuilder, GetFrame(),
+                                                           this);
+  }
+  return NS_OK;
+}
+
+void nsButtonFrameRenderer::GetButtonInnerFocusRect(const nsRect& aRect,
+                                                    nsRect& aResult) {
+  aResult = aRect;
+  aResult.Deflate(mFrame->GetUsedBorderAndPadding());
+
+  if (mInnerFocusStyle) {
+    nsMargin innerFocusPadding(0, 0, 0, 0);
+    mInnerFocusStyle->StylePadding()->GetPadding(innerFocusPadding);
+
+    nsMargin framePadding = mFrame->GetUsedPadding();
+
+    innerFocusPadding.top = std::min(innerFocusPadding.top, framePadding.top);
+    innerFocusPadding.right =
+        std::min(innerFocusPadding.right, framePadding.right);
+    innerFocusPadding.bottom =
+        std::min(innerFocusPadding.bottom, framePadding.bottom);
+    innerFocusPadding.left =
+        std::min(innerFocusPadding.left, framePadding.left);
+
+    aResult.Inflate(innerFocusPadding);
+  }
+}
+
+ImgDrawResult nsButtonFrameRenderer::PaintInnerFocusBorder(
+    nsDisplayListBuilder* aBuilder, nsPresContext* aPresContext,
+    gfxContext& aRenderingContext, const nsRect& aDirtyRect,
+    const nsRect& aRect) {
+  // we draw the -moz-focus-inner border just inside the button's
+  // normal border and padding, to match Windows themes.
+
+  nsRect rect;
+
+  PaintBorderFlags flags = aBuilder->ShouldSyncDecodeImages()
+                               ? PaintBorderFlags::SyncDecodeImages
+                               : PaintBorderFlags();
+
+  ImgDrawResult result = ImgDrawResult::SUCCESS;
+
+  if (mInnerFocusStyle) {
+    GetButtonInnerFocusRect(aRect, rect);
+
+    result &=
+        nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, mFrame,
+                                    aDirtyRect, rect, mInnerFocusStyle, flags);
+  }
+
+  return result;
+}
+
+Maybe<nsCSSBorderRenderer>
+nsButtonFrameRenderer::CreateInnerFocusBorderRenderer(
+    nsDisplayListBuilder* aBuilder, nsPresContext* aPresContext,
+    gfxContext* aRenderingContext, const nsRect& aDirtyRect,
+    const nsRect& aRect, bool* aBorderIsEmpty) {
+  if (mInnerFocusStyle) {
+    nsRect rect;
+    GetButtonInnerFocusRect(aRect, rect);
+
+    gfx::DrawTarget* dt =
+        aRenderingContext ? aRenderingContext->GetDrawTarget() : nullptr;
+    return nsCSSRendering::CreateBorderRenderer(
+        aPresContext, dt, mFrame, aDirtyRect, rect, mInnerFocusStyle,
+        aBorderIsEmpty);
+  }
+
+  return Nothing();
+}
+
+ImgDrawResult nsButtonFrameRenderer::PaintBorder(nsDisplayListBuilder* aBuilder,
+                                                 nsPresContext* aPresContext,
+                                                 gfxContext& aRenderingContext,
+                                                 const nsRect& aDirtyRect,
+                                                 const nsRect& aRect) {
+  // get the button rect this is inside the focus and outline rects
+  nsRect buttonRect = aRect;
+  ComputedStyle* context = mFrame->Style();
+
+  PaintBorderFlags borderFlags = aBuilder->ShouldSyncDecodeImages()
+                                     ? PaintBorderFlags::SyncDecodeImages
+                                     : PaintBorderFlags();
+
+  nsCSSRendering::PaintBoxShadowInner(aPresContext, aRenderingContext, mFrame,
+                                      buttonRect);
+
+  ImgDrawResult result =
+      nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, mFrame,
+                                  aDirtyRect, buttonRect, context, borderFlags);
+
+  return result;
+}
+
+/**
+ * Call this when styles change
+ */
+void nsButtonFrameRenderer::ReResolveStyles(nsPresContext* aPresContext) {
+  // get all the styles
+  ServoStyleSet* styleSet = aPresContext->StyleSet();
+
+  // get styles assigned to -moz-focus-inner (ie dotted border on Windows)
+  mInnerFocusStyle = styleSet->ProbePseudoElementStyle(
+      *mFrame->GetContent()->AsElement(), PseudoStyleType::mozFocusInner,
+      mFrame->Style());
+}
+
+ComputedStyle* nsButtonFrameRenderer::GetComputedStyle(int32_t aIndex) const {
+  switch (aIndex) {
+    case NS_BUTTON_RENDERER_FOCUS_INNER_CONTEXT_INDEX:
+      return mInnerFocusStyle;
+    default:
+      return nullptr;
+  }
+}
+
+void nsButtonFrameRenderer::SetComputedStyle(int32_t aIndex,
+                                             ComputedStyle* aComputedStyle) {
+  switch (aIndex) {
+    case NS_BUTTON_RENDERER_FOCUS_INNER_CONTEXT_INDEX:
+      mInnerFocusStyle = aComputedStyle;
+      break;
+  }
+}