Bug 1599176 - Use sequence for borderBoxSize and contentBoxSize in ResizeObserverEntry. r=smaug,dholbert

Based on the spec, we should use FrozenArray for these two attributes.
However, we don't support FrozenArray in Gecko now, so use sequence.

spec: https://drafts.csswg.org/resize-observer/#resize-observer-entry-interface

Differential Revision: https://phabricator.services.mozilla.com/D120276

dom/base/ResizeObserver.cpp

@@ -342,6 +342,30 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ResizeObserverEntry)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
 NS_INTERFACE_MAP_END
 
+void ResizeObserverEntry::GetBorderBoxSize(
+    nsTArray<RefPtr<ResizeObserverSize>>& aRetVal) const {
+  // In the resize-observer-1 spec, there will only be a single
+  // ResizeObserverSize returned in the FrozenArray for now.
+  //
+  // Note: the usage of FrozenArray is to support elements that have multiple
+  // fragments, which occur in multi-column scenarios.
+  // https://drafts.csswg.org/resize-observer/#resize-observer-entry-interface
+  aRetVal.Clear();
+  aRetVal.AppendElement(mBorderBoxSize);
+}
+
+void ResizeObserverEntry::GetContentBoxSize(
+    nsTArray<RefPtr<ResizeObserverSize>>& aRetVal) const {
+  // In the resize-observer-1 spec, there will only be a single
+  // ResizeObserverSize returned in the FrozenArray for now.
+  //
+  // Note: the usage of FrozenArray is to support elements that have multiple
+  // fragments, which occur in multi-column scenarios.
+  // https://drafts.csswg.org/resize-observer/#resize-observer-entry-interface
+  aRetVal.Clear();
+  aRetVal.AppendElement(mContentBoxSize);
+}
+
 void ResizeObserverEntry::SetBorderBoxSize(const nsSize& aSize) {
   nsIFrame* frame = mTarget->GetPrimaryFrame();
   const WritingMode wm = frame ? frame->GetWritingMode() : WritingMode();

dom/base/ResizeObserver.h

@@ -38,8 +38,8 @@ class ResizeObservation final : public LinkedListElement<ResizeObservation> {
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(ResizeObservation)
   NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(ResizeObservation)
 
-  ResizeObservation(Element&, ResizeObserver&,
-                    ResizeObserverBoxOptions, WritingMode);
+  ResizeObservation(Element&, ResizeObserver&, ResizeObserverBoxOptions,
+                    WritingMode);
 
   Element* Target() const { return mTarget; }
 
@@ -207,8 +207,8 @@ class ResizeObserverEntry final : public nsISupports, public nsWrapperCache {
    * Returns target's logical border-box size and content-box size as
    * ResizeObserverSize.
    */
-  ResizeObserverSize* BorderBoxSize() const { return mBorderBoxSize; }
-  ResizeObserverSize* ContentBoxSize() const { return mContentBoxSize; }
+  void GetBorderBoxSize(nsTArray<RefPtr<ResizeObserverSize>>& aRetVal) const;
+  void GetContentBoxSize(nsTArray<RefPtr<ResizeObserverSize>>& aRetVal) const;
 
  private:
   ~ResizeObserverEntry() = default;

dom/webidl/ResizeObserver.webidl

@@ -36,8 +36,12 @@ callback ResizeObserverCallback = void (sequence<ResizeObserverEntry> entries, R
 interface ResizeObserverEntry {
     readonly attribute Element target;
     readonly attribute DOMRectReadOnly contentRect;
-    readonly attribute ResizeObserverSize borderBoxSize;
-    readonly attribute ResizeObserverSize contentBoxSize;
+    // We are using [Pure, Cached, Frozen] sequence until `FrozenArray` is implemented.
+    // See https://bugzilla.mozilla.org/show_bug.cgi?id=1236777 for more details.
+    [Frozen, Cached, Pure]
+    readonly attribute sequence<ResizeObserverSize> borderBoxSize;
+    [Frozen, Cached, Pure]
+    readonly attribute sequence<ResizeObserverSize> contentBoxSize;
 };
 
 [Pref="layout.css.resizeobserver.enabled",

testing/web-platform/meta/resize-observer/idlharness.window.js.ini

@@ -5,12 +5,6 @@
   [ResizeObserverEntry interface: attribute devicePixelContentBoxSize]
     expected: FAIL
 
-  [ResizeObserverEntry interface: entry must inherit property "contentBoxSize" with the proper type]
-    expected: FAIL
-
-  [ResizeObserverEntry interface: entry must inherit property "borderBoxSize" with the proper type]
-    expected: FAIL
-
   [ResizeObserverEntry must be primary interface of entry]
     expected:
       if (os == "linux") and debug and webrender and not fission: [PASS, FAIL]

testing/web-platform/meta/resize-observer/observe.html.ini

@@ -8,33 +8,6 @@ bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1587973
   [test6: iframe notifications]
     expected: [PASS, FAIL]
 
-  [test14: observe the same target but using a different box should override the previous one]
-    expected: FAIL
-
-  [test15: an observation is fired with box dimensions 0 when element's display property is set to inline]
-    expected: FAIL
-
-  [test11: simple observation with vertical writing mode]
-    expected: FAIL
-
-  [test10: simple border-box observation]
-    expected: FAIL
-
-  [test13: an observation is fired after the change of writing mode when box's specified size comes from physical size properties.]
-    expected: FAIL
-
-  [test12: no observation is fired after the change of writing mode when box's specified size comes from logical size properties.]
-    expected: FAIL
-
-  [test9: simple content-box observation but keep border-box size unchanged]
-    expected: FAIL
-
-  [test8: simple content-box observation]
-    expected: FAIL
-
   [test18: an observation is fired when device-pixel-content-box is being observed]
     expected: FAIL
 
-  [test17: Box sizing snd Resize Observer notifications]
-    expected: FAIL
-

testing/web-platform/meta/resize-observer/svg.html.ini

@@ -5,24 +5,9 @@ bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1587973
   [test15: observe svg:text content and border box]
     expected: FAIL
 
-  [test12: observe svg:rect content box]
-    expected: FAIL
-
-  [guard]
-    expected: NOTRUN
-
-  [test14: observe g:rect content and border box]
-    expected: FAIL
-
-  [test16: observe g:rect content, border and device-pixel-content boxes]
-    expected: FAIL
-
   [guard]
     expected: NOTRUN
 
   [test16: observe g:rect content, border and device-pixel-content boxes]
     expected: FAIL
 
-  [test13: observe svg:rect border box]
-    expected: FAIL
-