Bug 1767124 - Change the return type of nsLayoutUtils::GetTransformToAncestorScaleExcludingAnimated to MatrixScalesDouble. r=botond

Differential Revision: https://phabricator.services.mozilla.com/D147100

layout/base/nsLayoutUtils.cpp

@@ -2144,15 +2144,15 @@ static Matrix4x4Flagged GetTransformToAncestorExcludingAnimated(
   return ctm;
 }
 
-gfxSize nsLayoutUtils::GetTransformToAncestorScaleExcludingAnimated(
+MatrixScalesDouble nsLayoutUtils::GetTransformToAncestorScaleExcludingAnimated(
     nsIFrame* aFrame) {
   Matrix4x4Flagged transform = GetTransformToAncestorExcludingAnimated(
       aFrame, nsLayoutUtils::GetDisplayRootFrame(aFrame));
   Matrix transform2D;
   if (transform.Is2D(&transform2D)) {
-    return ThebesMatrix(transform2D).ScaleFactors().ToSize();
+    return ThebesMatrix(transform2D).ScaleFactors();
   }
-  return gfxSize(1, 1);
+  return MatrixScalesDouble();
 }
 
 const nsIFrame* nsLayoutUtils::FindNearestCommonAncestorFrame(

layout/base/nsLayoutUtils.h

@@ -955,7 +955,8 @@ class nsLayoutUtils {
    * If some frame on the path from aFrame to the display root frame may have an
    * animated scale, returns the identity scale factors.
    */
-  static gfxSize GetTransformToAncestorScaleExcludingAnimated(nsIFrame* aFrame);
+  static MatrixScalesDouble GetTransformToAncestorScaleExcludingAnimated(
+      nsIFrame* aFrame);
 
   /**
    * Gets a scale that includes CSS transforms in this process as well as the

layout/generic/nsImageFrame.cpp

@@ -1080,9 +1080,12 @@ void nsImageFrame::MaybeDecodeForPredictedSize() {
 
   // OK, we're ready to decode. Compute the scale to the screen...
   mozilla::PresShell* presShell = PresContext()->PresShell();
-  LayoutDeviceToScreenScale2D resolutionToScreen(
+  MatrixScalesDouble scale =
-      presShell->GetCumulativeResolution() *
+      ScaleFactor<UnknownUnits, UnknownUnits>(
-      nsLayoutUtils::GetTransformToAncestorScaleExcludingAnimated(this));
+          presShell->GetCumulativeResolution()) *
+      nsLayoutUtils::GetTransformToAncestorScaleExcludingAnimated(this);
+  auto resolutionToScreen =
+      ViewAs<LayoutDeviceToScreenScale2D>(scale.ConvertTo<float>());
 
   // If we are in a remote browser, then apply scaling from ancestor browsers
   if (BrowserChild* browserChild = BrowserChild::GetFrom(presShell)) {