Bug 1450927 - add getBoundsInCSSPixels XPCOM method. r=surkov r=jld

MozReview-Commit-ID: CTANPVQw1sG

accessible/generic/Accessible-inl.h

@@ -144,6 +144,12 @@ Accessible::InsertAfter(Accessible* aNewChild, Accessible* aRefChild)
                        aNewChild);
 }
 
+inline nsIntRect
+Accessible::Bounds() const
+{
+  return BoundsInAppUnits().ToNearestPixels(mDoc->PresContext()->AppUnitsPerDevPixel());
+}
+
 } // namespace a11y
 } // namespace mozilla
 

accessible/generic/Accessible.cpp

@@ -670,32 +670,31 @@ Accessible::RelativeBounds(nsIFrame** aBoundingFrame) const
   return nsRect();
 }
 
-nsIntRect
-Accessible::Bounds() const
+nsRect
+Accessible::BoundsInAppUnits() const
 {
   nsIFrame* boundingFrame = nullptr;
   nsRect unionRectTwips = RelativeBounds(&boundingFrame);
-  if (!boundingFrame)
-    return nsIntRect();
-
-  nsIntRect screenRect;
-  nsPresContext* presContext = mDoc->PresContext();
-  screenRect.SetRect(presContext->AppUnitsToDevPixels(unionRectTwips.X()),
-                     presContext->AppUnitsToDevPixels(unionRectTwips.Y()),
-                     presContext->AppUnitsToDevPixels(unionRectTwips.Width()),
-                     presContext->AppUnitsToDevPixels(unionRectTwips.Height()));
+  if (!boundingFrame) {
+    return nsRect();
+  }
 
   // We need to take into account a non-1 resolution set on the presshell.
   // This happens in mobile platforms with async pinch zooming. Here we
   // scale the bounds before adding the screen-relative offset.
-  screenRect.ScaleRoundOut(presContext->PresShell()->GetResolution());
+  unionRectTwips.ScaleRoundOut(mDoc->PresContext()->PresShell()->GetResolution());
   // We have the union of the rectangle, now we need to put it in absolute
   // screen coords.
-  nsIntRect orgRectPixels = boundingFrame->GetScreenRectInAppUnits().
-    ToNearestPixels(presContext->AppUnitsPerDevPixel());
-  screenRect.MoveBy(orgRectPixels.X(), orgRectPixels.Y());
+  nsRect orgRectPixels = boundingFrame->GetScreenRectInAppUnits();
+  unionRectTwips.MoveBy(orgRectPixels.X(), orgRectPixels.Y());
 
-  return screenRect;
+  return unionRectTwips;
+}
+
+nsIntRect
+Accessible::BoundsInCSSPixels() const
+{
+  return BoundsInAppUnits().ToNearestPixels(mDoc->PresContext()->AppUnitsPerCSSPixel());
 }
 
 void

accessible/generic/Accessible.h

@@ -509,10 +509,20 @@ public:
   virtual void AppendTextTo(nsAString& aText, uint32_t aStartOffset = 0,
                             uint32_t aLength = UINT32_MAX);
 
+  /**
+   * Return boundaries in screen coordinates in app units.
+   */
+  virtual nsRect BoundsInAppUnits() const;
+
   /**
    * Return boundaries in screen coordinates.
    */
-  virtual nsIntRect Bounds() const;
+  nsIntRect Bounds() const;
+
+  /**
+   * Return boundaries in screen coordinates in CSS pixels.
+   */
+  virtual nsIntRect BoundsInCSSPixels() const;
 
   /**
    * Return boundaries rect relative the bounding frame.

accessible/generic/ApplicationAccessible.cpp

@@ -116,10 +116,10 @@ ApplicationAccessible::RelationByType(RelationType aRelationType)
   return Relation();
 }
 
-nsIntRect
-ApplicationAccessible::Bounds() const
+nsRect
+ApplicationAccessible::BoundsInAppUnits() const
 {
-  return nsIntRect();
+  return nsRect();
 }
 
 ////////////////////////////////////////////////////////////////////////////////

accessible/generic/ApplicationAccessible.h

@@ -36,7 +36,7 @@ public:
 
   // Accessible
   virtual void Shutdown() override;
-  virtual nsIntRect Bounds() const override;
+  virtual nsRect BoundsInAppUnits() const override;
   virtual already_AddRefed<nsIPersistentProperties> NativeAttributes() override;
   virtual GroupPos GroupPosition() override;
   virtual ENameValueFlag Name(nsString& aName) override;

accessible/html/HTMLListAccessible.cpp

@@ -74,15 +74,15 @@ HTMLLIAccessible::NativeState()
   return HyperTextAccessibleWrap::NativeState() | states::READONLY;
 }
 
-nsIntRect
-HTMLLIAccessible::Bounds() const
+nsRect
+HTMLLIAccessible::BoundsInAppUnits() const
 {
-  nsIntRect rect = AccessibleWrap::Bounds();
-  if (rect.IsEmpty() || !mBullet || mBullet->IsInside())
+  nsRect rect = AccessibleWrap::BoundsInAppUnits();
+  if (rect.IsEmpty() || !mBullet || mBullet->IsInside()) {
     return rect;
+  }
 
-  nsIntRect bulletRect = mBullet->Bounds();
-
+  nsRect bulletRect = mBullet->BoundsInAppUnits();
   // Move x coordinate of list item over to cover bullet as well
   rect.SetLeftEdge(bulletRect.X());
   return rect;

accessible/html/HTMLListAccessible.h

@@ -51,7 +51,7 @@ public:
 
   // Accessible
   virtual void Shutdown() override;
-  virtual nsIntRect Bounds() const override;
+  virtual nsRect BoundsInAppUnits() const override;
   virtual a11y::role NativeRole() override;
   virtual uint64_t NativeState() override;
 

accessible/interfaces/gecko/IGeckoCustom.idl

@@ -12,6 +12,10 @@ interface IGeckoCustom : IUnknown
 {
   [propget] HRESULT ID([out, retval] unsigned __int64* aID);
   [propget] HRESULT anchorCount([out, retval] long* aCount);
+  [propget] HRESULT boundsInCSSPixels([out] __int32* aX,
+                                      [out] __int32* aY,
+                                      [out] __int32* aWidth,
+                                      [out, retval] __int32* aHeight);
   [propget] HRESULT DOMNodeID([out, retval] BSTR* aID);
   [propget] HRESULT minimumIncrement([out, retval] double* aIncrement);
   [propget] HRESULT mozState([out, retval] unsigned __int64* aState);

accessible/interfaces/nsIAccessible.idl

@@ -20,11 +20,11 @@ class Accessible;
 %}
 
 /**
- * A cross-platform interface that supports platform-specific 
+ * A cross-platform interface that supports platform-specific
  * accessibility APIs like MSAA and ATK. Contains the sum of what's needed
  * to support IAccessible as well as ATK's generic accessibility objects.
  * Can also be used by in-process accessibility clients to get information
- * about objects in the accessible tree. The accessible tree is a subset of 
+ * about objects in the accessible tree. The accessible tree is a subset of
  * nodes in the DOM tree -- such as documents, focusable elements and text.
  * Mozilla creates the implementations of nsIAccessible on demand.
  * See http://www.mozilla.org/projects/ui/accessibility for more information.
@@ -56,7 +56,7 @@ interface nsIAccessible : nsISupports
    * Last child in accessible tree
    */
   readonly attribute nsIAccessible lastChild;
-  
+
   /**
    * Array of all this element's children.
    */
@@ -124,7 +124,7 @@ interface nsIAccessible : nsISupports
   /**
    * Provides localized string of accesskey name, such as Alt+D.
    * The modifier may be affected by user and platform preferences.
-   * Usually alt+letter, or just the letter alone for menu items. 
+   * Usually alt+letter, or just the letter alone for menu items.
    */
   readonly attribute AString accessKey;
 
@@ -226,10 +226,16 @@ interface nsIAccessible : nsISupports
 
   /**
    * Return accessible's x and y coordinates relative to the screen and
-   * accessible's width and height.
+   * accessible's width and height in Dev pixels.
    */
   void getBounds(out long x, out long y, out long width, out long height);
 
+  /**
+   * Return accessible's x and y coordinates relative to the screen and
+   * accessible's width and height in CSS pixels.
+   */
+  void getBoundsInCSSPixels(out long aX, out long aY, out long aWidth, out long aHeight);
+
   /**
    * Add or remove this accessible to the current selection
    */

accessible/ipc/ProxyAccessibleShared.h

@@ -253,6 +253,7 @@ ProxyAccessible* FocusedChild();
 ProxyAccessible* ChildAtPoint(int32_t aX, int32_t aY,
     Accessible::EWhichChildAtPoint aWhichChild);
 nsIntRect Bounds();
+nsIntRect BoundsInCSSPixels();
 
 void Language(nsString& aLocale);
 void DocType(nsString& aType);

accessible/ipc/other/DocAccessibleChild.cpp

@@ -1983,6 +1983,30 @@ DocAccessibleChild::RecvExtents(const uint64_t& aID,
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult
+DocAccessibleChild::RecvExtentsInCSSPixels(const uint64_t& aID,
+                                           int32_t* aX,
+                                           int32_t* aY,
+                                           int32_t* aWidth,
+                                           int32_t* aHeight)
+{
+  *aX = 0;
+  *aY = 0;
+  *aWidth = 0;
+  *aHeight = 0;
+  Accessible* acc = IdToAccessible(aID);
+  if (acc && !acc->IsDefunct()) {
+    nsIntRect screenRect = acc->BoundsInCSSPixels();
+    if (!screenRect.IsEmpty()) {
+      *aX = screenRect.x;
+      *aY = screenRect.y;
+      *aWidth = screenRect.width;
+      *aHeight = screenRect.height;
+    }
+  }
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult
 DocAccessibleChild::RecvDOMNodeID(const uint64_t& aID, nsString* aDOMNodeID)
 {

accessible/ipc/other/DocAccessibleChild.h

@@ -470,6 +470,11 @@ public:
                                               int32_t* aY,
                                               int32_t* aWidth,
                                               int32_t* aHeight) override;
+  virtual mozilla::ipc::IPCResult RecvExtentsInCSSPixels(const uint64_t& aID,
+                                                         int32_t* aX,
+                                                         int32_t* aY,
+                                                         int32_t* aWidth,
+                                                         int32_t* aHeight) override;
   virtual mozilla::ipc::IPCResult RecvDOMNodeID(const uint64_t& aID, nsString* aDOMNodeID) override;
 private:
 

accessible/ipc/other/PDocAccessible.ipdl

@@ -265,6 +265,8 @@ child:
 
   nested(inside_sync) sync Extents(uint64_t aID, bool aNeedsScreenCoords)
     returns(int32_t aX, int32_t aY, int32_t aWidth, int32_t aHeight);
+  nested(inside_sync) sync ExtentsInCSSPixels(uint64_t aID)
+    returns(int32_t aX, int32_t aY, int32_t aWidth, int32_t aHeight);
   nested(inside_sync) sync DOMNodeID(uint64_t aID) returns(nsString aDOMNodeID);
 };
 

accessible/ipc/other/ProxyAccessible.cpp

@@ -1013,6 +1013,16 @@ ProxyAccessible::Bounds()
   return rect;
 }
 
+nsIntRect
+ProxyAccessible::BoundsInCSSPixels()
+{
+  nsIntRect rect;
+  Unused << mDoc->SendExtentsInCSSPixels(mID,
+                                         &rect.x, &rect.y,
+                                         &rect.width, &rect.height);
+  return rect;
+}
+
 void
 ProxyAccessible::Language(nsString& aLocale)
 {

accessible/ipc/win/ProxyAccessible.cpp

@@ -235,6 +235,19 @@ ProxyAccessible::Bounds()
   return rect;
 }
 
+nsIntRect
+ProxyAccessible::BoundsInCSSPixels()
+{
+  RefPtr<IGeckoCustom> custom = QueryInterface<IGeckoCustom>(this);
+  if (!custom) {
+    return nsIntRect();
+  }
+
+  nsIntRect rect;
+  HRESULT hr = custom->get_boundsInCSSPixels(&rect.x, &rect.y, &rect.width, &rect.height);
+  return rect;
+}
+
 void
 ProxyAccessible::Language(nsString& aLocale)
 {

accessible/tests/browser/bounds/browser_test_zoom.js

@@ -6,6 +6,8 @@
 
 /* import-globals-from ../../mochitest/layout.js */
 
+/* global getContentDPR */
+
 async function getContentBoundsForDOMElm(browser, id) {
   return ContentTask.spawn(browser, id, contentId => {
     this.ok = ok;
@@ -17,12 +19,13 @@ async function testContentBounds(browser, acc) {
   let [expectedX, expectedY, expectedWidth, expectedHeight] =
     await getContentBoundsForDOMElm(browser, getAccessibleDOMNodeID(acc));
 
-  let [x, y, width, height] = getBounds(acc);
+  let contentDPR = await getContentDPR(browser);
+  let [x, y, width, height] = getBounds(acc, contentDPR);
   let prettyAccName = prettyName(acc);
   is(x, expectedX, "Wrong x coordinate of " + prettyAccName);
   is(y, expectedY, "Wrong y coordinate of " + prettyAccName);
   is(width, expectedWidth, "Wrong width of " + prettyAccName);
-  is(height, expectedHeight, "Wrong height of " + prettyAccName);
+  ok(height >= expectedHeight, "Wrong height of " + prettyAccName);
 }
 
 async function runTests(browser, accDoc) {

accessible/tests/browser/bounds/browser_test_zoom_text.js

@@ -6,26 +6,29 @@
 
 /* import-globals-from ../../mochitest/layout.js */
 
+/* global getContentDPR */
+
 async function runTests(browser, accDoc) {
-  function testTextNode(id) {
+  async function testTextNode(id) {
     let hyperTextNode = findAccessibleChildByID(accDoc, id);
     let textNode = hyperTextNode.firstChild;
 
-    let [x, y, width, height] = getBounds(textNode);
+    let contentDPR = await getContentDPR(browser);
+    let [x, y, width, height] = getBounds(textNode, contentDPR);
     testTextBounds(hyperTextNode, 0, -1, [x, y, width, height],
                    COORDTYPE_SCREEN_RELATIVE);
   }
 
   loadFrameScripts(browser, { name: "layout.js", dir: MOCHITESTS_DIR });
 
-  testTextNode("p1");
-  testTextNode("p2");
+  await testTextNode("p1");
+  await testTextNode("p2");
 
   await ContentTask.spawn(browser, {}, () => {
     zoomDocument(document, 2.0);
   });
 
-  testTextNode("p1");
+  await testTextNode("p1");
 
   await ContentTask.spawn(browser, {}, () => {
     zoomDocument(document, 1.0);

accessible/tests/browser/bounds/head.js

@@ -6,6 +6,9 @@
 
 // Load the shared-head file first.
 /* import-globals-from ../shared-head.js */
+
+/* exported getContentDPR */
+
 Services.scriptloader.loadSubScript(
   "chrome://mochitests/content/browser/accessible/tests/browser/shared-head.js",
   this);
@@ -14,3 +17,10 @@ Services.scriptloader.loadSubScript(
 // well as events.js.
 loadScripts({ name: "common.js", dir: MOCHITESTS_DIR },
             { name: "layout.js", dir: MOCHITESTS_DIR }, "events.js");
+
+/**
+ * Get content window DPR that can be different from parent window DPR.
+ */
+async function getContentDPR(browser) {
+  return ContentTask.spawn(browser, null, () => content.window.devicePixelRatio);
+}

accessible/tests/mochitest/bounds/test_list.html

@@ -46,8 +46,8 @@
          "Outside list item y should match to list item element y");
       ok(widthLI > widthLIElm,
          "Outside list item width=" + widthLI + " should be greater than list item element width=" + widthLIElm);
-      is(heightLI, heightLIElm,
-         "Outside list item height should match to list item element height");
+      ok(heightLI >= Math.trunc(heightLIElm),
+         "Outside list item height=" + heightLI + " should not be less than list item element height=" + heightLIElm);
 
       SimpleTest.finish();
     }

accessible/tests/mochitest/layout.js

@@ -199,12 +199,25 @@ function getPos(aID) {
 
 /**
  * Return the accessible coordinates and size relative to the screen in device
- * pixels.
+ * pixels. This methods also retrieves coordinates in CSS pixels and ensures that they
+ * match Dev pixels with a given device pixel ratio.
  */
-function getBounds(aID) {
-  var accessible = getAccessible(aID);
-  var x = {}, y = {}, width = {}, height = {};
+function getBounds(aID, aDPR = window.devicePixelRatio) {
+  const accessible = getAccessible(aID);
+  let x = {}, y = {}, width = {}, height = {};
+  let xInCSS = {}, yInCSS = {}, widthInCSS = {}, heightInCSS = {};
   accessible.getBounds(x, y, width, height);
+  accessible.getBoundsInCSSPixels(xInCSS, yInCSS, widthInCSS, heightInCSS);
+
+  isWithin(x.value / aDPR, xInCSS.value, 1,
+    "Heights in CSS pixels is calculated correctly");
+  isWithin(y.value / aDPR, yInCSS.value, 1,
+    "Heights in CSS pixels is calculated correctly");
+  isWithin(width.value / aDPR, widthInCSS.value, 1,
+    "Heights in CSS pixels is calculated correctly");
+  isWithin(height.value / aDPR, heightInCSS.value, 1,
+    "Heights in CSS pixels is calculated correctly");
+
   return [x.value, y.value, width.value, height.value];
 }
 

accessible/windows/msaa/GeckoCustom.cpp

@@ -20,6 +20,21 @@ GeckoCustom::get_anchorCount(long* aCount)
   return S_OK;
 }
 
+HRESULT
+GeckoCustom::get_boundsInCSSPixels(int32_t* aX, int32_t* aY,
+                                   int32_t* aWidth, int32_t* aHeight)
+{
+  nsIntRect bounds = mAcc->BoundsInCSSPixels();
+  if (!bounds.IsEmpty()) {
+    *aX = bounds.X();
+    *aY = bounds.Y();
+    *aWidth = bounds.Width();
+    *aHeight = bounds.Height();
+  }
+
+  return S_OK;
+}
+
 HRESULT
 GeckoCustom::get_DOMNodeID(BSTR* aID)
 {

accessible/windows/msaa/GeckoCustom.h

@@ -27,6 +27,8 @@ public:
   DECL_IUNKNOWN
 
   virtual STDMETHODIMP get_anchorCount(long* aCount);
+  virtual STDMETHODIMP get_boundsInCSSPixels(int32_t* aX, int32_t* aY,
+                                             int32_t* aWidth, int32_t* aHeight);
   virtual STDMETHODIMP get_DOMNodeID(BSTR* aID);
   virtual STDMETHODIMP get_ID(uint64_t* aID);
   virtual STDMETHODIMP get_minimumIncrement(double* aIncrement);

accessible/xpcom/xpcAccessible.cpp

@@ -456,6 +456,34 @@ xpcAccessible::GetBounds(int32_t* aX, int32_t* aY,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+xpcAccessible::GetBoundsInCSSPixels(int32_t* aX, int32_t* aY,
+                                  int32_t* aWidth, int32_t* aHeight)
+{
+  NS_ENSURE_ARG_POINTER(aX);
+  *aX = 0;
+  NS_ENSURE_ARG_POINTER(aY);
+  *aY = 0;
+  NS_ENSURE_ARG_POINTER(aWidth);
+  *aWidth = 0;
+  NS_ENSURE_ARG_POINTER(aHeight);
+  *aHeight = 0;
+
+  if (IntlGeneric().IsNull()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsIntRect rect;
+  if (Accessible* acc = IntlGeneric().AsAccessible()) {
+    rect = acc->BoundsInCSSPixels();
+  } else {
+    rect = IntlGeneric().AsProxy()->BoundsInCSSPixels();
+  }
+
+  rect.GetRect(aX, aY, aWidth, aHeight);
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 xpcAccessible::GroupPosition(int32_t* aGroupLevel,
                              int32_t* aSimilarItemsInGroup,

accessible/xpcom/xpcAccessible.h

@@ -60,6 +60,8 @@ public:
     final;
   NS_IMETHOD GetBounds(int32_t* aX, int32_t* aY,
                        int32_t* aWidth, int32_t* aHeight) final;
+  NS_IMETHOD GetBoundsInCSSPixels(int32_t* aX, int32_t* aY,
+                                  int32_t* aWidth, int32_t* aHeight) final;
   NS_IMETHOD GroupPosition(int32_t* aGroupLevel, int32_t* aSimilarItemsInGroup,
                            int32_t* aPositionInGroup) final;
   NS_IMETHOD GetRelationByType(uint32_t aType,

accessible/xul/XULTreeAccessible.cpp

@@ -723,22 +723,24 @@ XULTreeItemAccessibleBase::FocusedChild()
 }
 
 nsIntRect
-XULTreeItemAccessibleBase::Bounds() const
+XULTreeItemAccessibleBase::BoundsInCSSPixels() const
 {
   // Get x coordinate and width from treechildren element, get y coordinate and
   // height from tree cell.
 
   nsCOMPtr<nsIBoxObject> boxObj = nsCoreUtils::GetTreeBodyBoxObject(mTree);
-  if (!boxObj)
+  if (!boxObj) {
     return nsIntRect();
+  }
 
   nsCOMPtr<nsITreeColumn> column = nsCoreUtils::GetFirstSensibleColumn(mTree);
 
   int32_t x = 0, y = 0, width = 0, height = 0;
   nsresult rv = mTree->GetCoordsForCellItem(mRow, column, EmptyString(),
                                             &x, &y, &width, &height);
-  if (NS_FAILED(rv))
+  if (NS_FAILED(rv)) {
     return nsIntRect();
+  }
 
   boxObj->GetWidth(&width);
 
@@ -749,11 +751,18 @@ XULTreeItemAccessibleBase::Bounds() const
   x = tcX;
   y += tcY;
 
+  return nsIntRect(x, y, width, height);
+}
+
+nsRect
+XULTreeItemAccessibleBase::BoundsInAppUnits() const
+{
+  nsIntRect bounds = BoundsInCSSPixels();
   nsPresContext* presContext = mDoc->PresContext();
-  return nsIntRect(presContext->CSSPixelsToDevPixels(x),
-                   presContext->CSSPixelsToDevPixels(y),
-                   presContext->CSSPixelsToDevPixels(width),
-                   presContext->CSSPixelsToDevPixels(height));
+  return nsRect(presContext->CSSPixelsToAppUnits(bounds.X()),
+                presContext->CSSPixelsToAppUnits(bounds.Y()),
+                presContext->CSSPixelsToAppUnits(bounds.Width()),
+                presContext->CSSPixelsToAppUnits(bounds.Height()));
 }
 
 void

accessible/xul/XULTreeAccessible.h

@@ -146,7 +146,8 @@ public:
 
   // Accessible
   virtual void Shutdown() override;
-  virtual nsIntRect Bounds() const override;
+  virtual nsRect BoundsInAppUnits() const override;
+  virtual nsIntRect BoundsInCSSPixels() const override;
   virtual GroupPos GroupPosition() override;
   virtual uint64_t NativeState() override;
   virtual uint64_t NativeInteractiveState() const override;

accessible/xul/XULTreeGridAccessible.cpp

@@ -495,20 +495,22 @@ XULTreeGridCellAccessible::Name(nsString& aName)
 }
 
 nsIntRect
-XULTreeGridCellAccessible::Bounds() const
+XULTreeGridCellAccessible::BoundsInCSSPixels() const
 {
   // Get bounds for tree cell and add x and y of treechildren element to
   // x and y of the cell.
   nsCOMPtr<nsIBoxObject> boxObj = nsCoreUtils::GetTreeBodyBoxObject(mTree);
-  if (!boxObj)
+  if (!boxObj) {
     return nsIntRect();
+  }
 
   int32_t x = 0, y = 0, width = 0, height = 0;
   nsresult rv = mTree->GetCoordsForCellItem(mRow, mColumn,
                                             NS_LITERAL_STRING("cell"),
                                             &x, &y, &width, &height);
-  if (NS_FAILED(rv))
+  if (NS_FAILED(rv)) {
     return nsIntRect();
+  }
 
   int32_t tcX = 0, tcY = 0;
   boxObj->GetScreenX(&tcX);
@@ -516,11 +518,18 @@ XULTreeGridCellAccessible::Bounds() const
   x += tcX;
   y += tcY;
 
+  return nsIntRect(x, y, width, height);
+}
+
+nsRect
+XULTreeGridCellAccessible::BoundsInAppUnits() const
+{
+  nsIntRect bounds = BoundsInCSSPixels();
   nsPresContext* presContext = mDoc->PresContext();
-  return nsIntRect(presContext->CSSPixelsToDevPixels(x),
-                   presContext->CSSPixelsToDevPixels(y),
-                   presContext->CSSPixelsToDevPixels(width),
-                   presContext->CSSPixelsToDevPixels(height));
+  return nsRect(presContext->CSSPixelsToAppUnits(bounds.X()),
+                presContext->CSSPixelsToAppUnits(bounds.Y()),
+                presContext->CSSPixelsToAppUnits(bounds.Width()),
+                presContext->CSSPixelsToAppUnits(bounds.Height()));
 }
 
 uint8_t

accessible/xul/XULTreeGridAccessible.h

@@ -126,7 +126,8 @@ public:
   // Accessible
   virtual void Shutdown() override;
   virtual TableCellAccessible* AsTableCell() override { return this; }
-  virtual nsIntRect Bounds() const override;
+  virtual nsRect BoundsInAppUnits() const override;
+  virtual nsIntRect BoundsInCSSPixels() const override;
   virtual ENameValueFlag Name(nsString& aName) override;
   virtual Accessible* FocusedChild() override;
   virtual already_AddRefed<nsIPersistentProperties> NativeAttributes() override;

ipc/ipdl/sync-messages.ini

@@ -594,6 +594,9 @@ platform = notwin
 [PDocAccessible::Extents]
 description =
 platform = notwin
+[PDocAccessible::ExtentsInCSSPixels]
+description =
+platform = notwin
 [PDocAccessible::DOMNodeID]
 description =
 platform = notwin