Bug 1667475 - Remove FrameMetrics::mDisplayPortMargins. r=kats

The two existing uses were inconsistent in whether the margins
were relative to the visual viewport or the layout viewport.

We could fix this, but it turns out both uses are readily
refactored to not need the field, so this patch removes the
field.

Differential Revision: https://phabricator.services.mozilla.com/D91479

gfx/layers/FrameMetrics.h

@@ -89,7 +89,6 @@ struct FrameMetrics {
         mZoom(),
         mScrollGeneration(0),
         mRootCompositionSize(0, 0),
-        mDisplayPortMargins(0, 0, 0, 0),
         mPresShellId(-1),
         mLayoutViewport(0, 0, 0, 0),
         mExtraResolution(),
@@ -115,7 +114,6 @@ struct FrameMetrics {
            // don't compare mZoom
            mScrollGeneration == aOther.mScrollGeneration &&
            mRootCompositionSize == aOther.mRootCompositionSize &&
-           mDisplayPortMargins == aOther.mDisplayPortMargins &&
            mPresShellId == aOther.mPresShellId &&
            mLayoutViewport.IsEqualEdges(aOther.mLayoutViewport) &&
            mExtraResolution == aOther.mExtraResolution &&
@@ -353,14 +351,6 @@ struct FrameMetrics {
 
   const CSSSize& GetRootCompositionSize() const { return mRootCompositionSize; }
 
-  void SetDisplayPortMargins(const ScreenMargin& aDisplayPortMargins) {
-    mDisplayPortMargins = aDisplayPortMargins;
-  }
-
-  const ScreenMargin& GetDisplayPortMargins() const {
-    return mDisplayPortMargins;
-  }
-
   uint32_t GetPresShellId() const { return mPresShellId; }
 
   void SetPresShellId(uint32_t aPresShellId) { mPresShellId = aPresShellId; }

gfx/layers/LayersLogging.cpp

@@ -178,7 +178,6 @@ void AppendToString(std::stringstream& aStream, const FrameMetrics& m,
     }
     AppendToString(aStream, m.GetZoom(), "] [z=", "] }");
   } else {
-    AppendToString(aStream, m.GetDisplayPortMargins(), " [dpm=");
     AppendToString(aStream, m.GetRootCompositionSize(), "] [rcs=");
     AppendToString(aStream, m.GetLayoutViewport(), "] [v=");
     aStream << nsPrintfCString("] [z=(ld=%.3f r=%.3f",

gfx/layers/RepaintRequest.h

@@ -61,6 +61,7 @@ struct RepaintRequest {
         mIsScrollInfoLayer(false) {}
 
   RepaintRequest(const FrameMetrics& aOther,
+                 const ScreenMargin& aDisplayportMargins,
                  const ScrollOffsetUpdateType aScrollUpdateType,
                  bool aIsAnimationInProgress)
       : mScrollId(aOther.GetScrollId()),
@@ -71,7 +72,7 @@ struct RepaintRequest {
         mScrollOffset(aOther.GetVisualScrollOffset()),
         mZoom(aOther.GetZoom()),
         mScrollGeneration(aOther.GetScrollGeneration()),
-        mDisplayPortMargins(aOther.GetDisplayPortMargins()),
+        mDisplayPortMargins(aDisplayportMargins),
         mPresShellId(aOther.GetPresShellId()),
         mLayoutViewport(aOther.GetLayoutViewport()),
         mExtraResolution(aOther.GetExtraResolution()),

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -3913,13 +3913,14 @@ void AsyncPanZoomController::RequestContentRepaint(
 
   RecursiveMutexAutoLock lock(mRecursiveMutex);
   ParentLayerPoint velocity = GetVelocityVector();
-  Metrics().SetDisplayPortMargins(
-      CalculatePendingDisplayPort(Metrics(), velocity));
+  ScreenMargin displayportMargins =
+      CalculatePendingDisplayPort(Metrics(), velocity);
   Metrics().SetPaintRequestTime(TimeStamp::Now());
-  RequestContentRepaint(Metrics(), velocity, aUpdateType);
+  RequestContentRepaint(Metrics(), velocity, displayportMargins, aUpdateType);
 }
 
-static CSSRect GetDisplayPortRect(const FrameMetrics& aFrameMetrics) {
+static CSSRect GetDisplayPortRect(const FrameMetrics& aFrameMetrics,
+                                  const ScreenMargin& aDisplayportMargins) {
   // This computation is based on what happens in CalculatePendingDisplayPort.
   // If that changes then this might need to change too.
   // Note that the display port rect APZ computes is relative to the visual
@@ -3929,14 +3930,14 @@ static CSSRect GetDisplayPortRect(const FrameMetrics& aFrameMetrics) {
   // applied (in nsLayoutUtils::GetDisplayPort()) in this adjusted form.
   CSSRect baseRect(aFrameMetrics.GetVisualScrollOffset(),
                    aFrameMetrics.CalculateBoundedCompositedSizeInCssPixels());
-  baseRect.Inflate(aFrameMetrics.GetDisplayPortMargins() /
+  baseRect.Inflate(aDisplayportMargins /
                    aFrameMetrics.DisplayportPixelsPerCSSPixel());
   return baseRect;
 }
 
 void AsyncPanZoomController::RequestContentRepaint(
     const FrameMetrics& aFrameMetrics, const ParentLayerPoint& aVelocity,
-    RepaintUpdateType aUpdateType) {
+    const ScreenMargin& aDisplayportMargins, RepaintUpdateType aUpdateType) {
   RefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (!controller) {
     return;
@@ -3944,7 +3945,8 @@ void AsyncPanZoomController::RequestContentRepaint(
   MOZ_ASSERT(controller->IsRepaintThread());
 
   const bool isAnimationInProgress = !!mAnimation;
-  RepaintRequest request(aFrameMetrics, aUpdateType, isAnimationInProgress);
+  RepaintRequest request(aFrameMetrics, aDisplayportMargins, aUpdateType,
+                         isAnimationInProgress);
 
   // If we're trying to paint what we already think is painted, discard this
   // request since it's a pointless paint.
@@ -3975,7 +3977,7 @@ void AsyncPanZoomController::RequestContentRepaint(
       std::string str = info.str();
       mCheckerboardEvent->UpdateRendertraceProperty(
           CheckerboardEvent::RequestedDisplayPort,
-          GetDisplayPortRect(aFrameMetrics), str);
+          GetDisplayPortRect(aFrameMetrics, aDisplayportMargins), str);
     }
   }
 
@@ -4547,15 +4549,8 @@ void AsyncPanZoomController::NotifyLayersUpdated(
       sampledState.UpdateZoomProperties(Metrics());
     }
 
-    if (Metrics().GetDisplayPortMargins() != ScreenMargin()) {
-      // A non-zero display port margin here indicates a displayport has
-      // been set by a previous APZC for the content at this guid. The
-      // scrollable rect may have changed since then, making the margins
-      // wrong, so we need to calculate a new display port.
-      APZC_LOG("%p detected non-empty margins which probably need updating\n",
-               this);
-      needContentRepaint = true;
-    }
+    // Make sure we have an up-to-date set of displayport margins.
+    needContentRepaint = true;
   } else {
     // If we're not taking the aLayerMetrics wholesale we still need to pull
     // in some things into our local Metrics() because these things are
@@ -5092,8 +5087,8 @@ void AsyncPanZoomController::ZoomToRect(CSSRect aRect, const uint32_t aFlags) {
     // Schedule a repaint now, so the new displayport will be painted before the
     // animation finishes.
     ParentLayerPoint velocity(0, 0);
-    endZoomToMetrics.SetDisplayPortMargins(
-        CalculatePendingDisplayPort(endZoomToMetrics, velocity));
+    ScreenMargin displayportMargins =
+        CalculatePendingDisplayPort(endZoomToMetrics, velocity);
     endZoomToMetrics.SetPaintRequestTime(TimeStamp::Now());
 
     RefPtr<GeckoContentController> controller = GetGeckoContentController();
@@ -5101,7 +5096,7 @@ void AsyncPanZoomController::ZoomToRect(CSSRect aRect, const uint32_t aFlags) {
       return;
     }
     if (controller->IsRepaintThread()) {
-      RequestContentRepaint(endZoomToMetrics, velocity,
+      RequestContentRepaint(endZoomToMetrics, velocity, displayportMargins,
                             RepaintUpdateType::eUserAction);
     } else {
       // See comment on similar code in RequestContentRepaint
@@ -5109,12 +5104,14 @@ void AsyncPanZoomController::ZoomToRect(CSSRect aRect, const uint32_t aFlags) {
 
       // use a local var to resolve the function overload
       auto func = static_cast<void (AsyncPanZoomController::*)(
-          const FrameMetrics&, const ParentLayerPoint&, RepaintUpdateType)>(
-          &AsyncPanZoomController::RequestContentRepaint);
+          const FrameMetrics&, const ParentLayerPoint&, const ScreenMargin&,
+          RepaintUpdateType)>(&AsyncPanZoomController::RequestContentRepaint);
       controller->DispatchToRepaintThread(
-          NewRunnableMethod<FrameMetrics, ParentLayerPoint, RepaintUpdateType>(
+          NewRunnableMethod<FrameMetrics, ParentLayerPoint, ScreenMargin,
+                            RepaintUpdateType>(
               "layers::AsyncPanZoomController::ZoomToRect", this, func,
-              endZoomToMetrics, velocity, RepaintUpdateType::eUserAction));
+              endZoomToMetrics, velocity, displayportMargins,
+              RepaintUpdateType::eUserAction));
     }
   }
 }

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -842,6 +842,7 @@ class AsyncPanZoomController {
    */
   void RequestContentRepaint(const FrameMetrics& aFrameMetrics,
                              const ParentLayerPoint& aVelocity,
+                             const ScreenMargin& aDisplayportMargins,
                              RepaintUpdateType aUpdateType);
 
   /**

layout/base/nsLayoutUtils.cpp

@@ -9245,13 +9245,6 @@ ScrollMetadata nsLayoutUtils::ComputeScrollMetadata(
                               ? metrics.GetCriticalDisplayPort()
                               : metrics.GetDisplayPort());
     }
-
-    DisplayPortMarginsPropertyData* marginsData =
-        static_cast<DisplayPortMarginsPropertyData*>(
-            aContent->GetProperty(nsGkAtoms::DisplayPortMargins));
-    if (marginsData) {
-      metrics.SetDisplayPortMargins(marginsData->mMargins);
-    }
   }
 
   nsIScrollableFrame* scrollableFrame = nullptr;