Bug 1667475 - Drop the 'aRelativeTo' parameter of GetDisplayPortForVisibilityTesting(). r=kats

The only caller passed in DisplayRelativeTo::ScrollFrame.

Removing this makes it easier to consolidate display port options
in a subsequent patch.

Differential Revision: https://phabricator.services.mozilla.com/D92014

layout/base/DisplayPortUtils.cpp

@@ -486,10 +486,8 @@ void DisplayPortUtils::MarkDisplayPortAsPainted(nsIContent* aContent) {
 }
 
 /* static */
-bool DisplayPortUtils::GetDisplayPortForVisibilityTesting(
-    nsIContent* aContent, nsRect* aResult,
-    DisplayportRelativeTo
-        aRelativeTo /* = DisplayportRelativeTo::ScrollPort */) {
+bool DisplayPortUtils::GetDisplayPortForVisibilityTesting(nsIContent* aContent,
+                                                          nsRect* aResult) {
   MOZ_ASSERT(aResult);
   // Since the base rect might not have been updated very recently, it's
   // possible to end up with an extra-large displayport at this point, if the
@@ -498,7 +496,7 @@ bool DisplayPortUtils::GetDisplayPortForVisibilityTesting(
   // call site is best-effort.
   bool usingDisplayPort = GetDisplayPortImpl(aContent, aResult, 1.0f,
                                              MaxSizeExceededBehaviour::Drop);
-  if (usingDisplayPort && aRelativeTo == DisplayportRelativeTo::ScrollFrame) {
+  if (usingDisplayPort) {
     TranslateFromScrollPortToScrollFrame(aContent, aResult);
   }
   return usingDisplayPort;

layout/base/DisplayPortUtils.h

@@ -96,14 +96,13 @@ class DisplayPortUtils {
 
   /**
    * @return the display port for the given element which should be used for
-   * visibility testing purposes.
+   * visibility testing purposes, relative to the scroll frame.
    *
    * If low-precision buffers are enabled, this is the critical display port;
    * otherwise, it's the same display port returned by GetDisplayPort().
    */
-  static bool GetDisplayPortForVisibilityTesting(
-      nsIContent* aContent, nsRect* aResult,
-      DisplayportRelativeTo aRelativeTo = DisplayportRelativeTo::ScrollPort);
+  static bool GetDisplayPortForVisibilityTesting(nsIContent* aContent,
+                                                 nsRect* aResult);
 
   enum class RepaintMode : uint8_t { Repaint, DoNotRepaint };
 

layout/base/PresShell.cpp

@@ -5892,8 +5892,7 @@ void PresShell::MarkFramesInSubtreeApproximatelyVisible(
     bool usingDisplayport =
         !ignoreDisplayPort &&
         DisplayPortUtils::GetDisplayPortForVisibilityTesting(
-            aFrame->GetContent(), &displayPort,
-            DisplayportRelativeTo::ScrollFrame);
+            aFrame->GetContent(), &displayPort);
 
     scrollFrame->NotifyApproximateFrameVisibilityUpdate(!usingDisplayport);