1 files changed, 22 insertions, 24 deletions

diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index 342375c019..edbd2ecffa 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -106,6 +106,10 @@ static mozilla::LazyLogModule sApzCtlLog("apz.controller");
   APZC_LOG("%p(%s scrollId=%" PRIu64 "): " fmt, (apzc),   \
            (apzc)->IsRootContent() ? "root" : "subframe", \
            (apzc)->GetScrollId(), ##__VA_ARGS__)
+#define APZC_LOGV_DETAIL(fmt, apzc, ...)                   \
+  APZC_LOGV("%p(%s scrollId=%" PRIu64 "): " fmt, (apzc),   \
+            (apzc)->IsRootContent() ? "root" : "subframe", \
+            (apzc)->GetScrollId(), ##__VA_ARGS__)
 
 #define APZC_LOG_FM_COMMON(fm, prefix, level, ...)                 \
   if (MOZ_LOG_TEST(sApzCtlLog, level)) {                           \
@@ -2248,6 +2252,11 @@ CSSRect AsyncPanZoomController::GetCurrentScrollRangeInCssPixels() const {
   return Metrics().CalculateScrollRange();
 }
 
+bool AsyncPanZoomController::AllowOneTouchPinch() const {
+  return StaticPrefs::apz_one_touch_pinch_enabled() &&
+         ZoomConstraintsAllowZoom();
+}
+
 // Return whether or not the underlying layer can be scrolled on either axis.
 bool AsyncPanZoomController::CanScroll(const InputData& aEvent) const {
   ParentLayerPoint delta = GetDeltaForEvent(aEvent);
@@ -4734,7 +4743,7 @@ bool AsyncPanZoomController::UpdateAnimation(
   // Even if there's no animation, if we have a scroll offset change pending due
   // to the frame delay, we need to keep compositing.
   if (mLastSampleTime == aSampleTime) {
-    APZC_LOG_DETAIL(
+    APZC_LOGV_DETAIL(
         "UpdateAnimation short-circuit, animation=%p, pending frame-delayed "
         "offset=%d\n",
         this, mAnimation.get(), HavePendingFrameDelayedOffset());
@@ -4754,8 +4763,8 @@ bool AsyncPanZoomController::UpdateAnimation(
   // so that e.g. a main-thread animation can stay in sync with user-driven
   // scrolling or a compositor animation.
   bool needComposite = SampleCompositedAsyncTransform(aProofOfLock);
-  APZC_LOG_DETAIL("UpdateAnimation needComposite=%d mAnimation=%p\n", this,
-                  needComposite, mAnimation.get());
+  APZC_LOGV_DETAIL("UpdateAnimation needComposite=%d mAnimation=%p\n", this,
+                   needComposite, mAnimation.get());
 
   TimeDuration sampleTimeDelta = aSampleTime - mLastSampleTime;
   mLastSampleTime = aSampleTime;
@@ -5581,17 +5590,6 @@ void AsyncPanZoomController::NotifyLayersUpdated(
         aScrollMetadata.GetOverscrollBehavior());
   }
 
-  if (needToReclampScroll) {
-    // Whenever scrollable rect or composition bounds has changed, we need to
-    // re-clamp the scroll offset since it may be out of bounds. Also note that
-    // we need to re-clamp before updating new scroll offsets from content since
-    // we will use the last scroll offset to reflect the new offsets.
-    ClampAndSetVisualScrollOffset(Metrics().GetVisualScrollOffset());
-    for (auto& sampledState : mSampledState) {
-      sampledState.ClampVisualScrollOffset(Metrics());
-    }
-  }
-
   bool instantScrollMayTriggerTransform = false;
   bool scrollOffsetUpdated = false;
   bool smoothScrollRequested = false;
@@ -5738,20 +5736,11 @@ void AsyncPanZoomController::NotifyLayersUpdated(
       relativeDelta =
           Some(Metrics().ApplyPureRelativeScrollUpdateFrom(scrollUpdate));
       Metrics().RecalculateLayoutViewportOffset();
-    } else if (scrollUpdate.GetType() == ScrollUpdateType::MergeableAbsolute) {
-      APZC_LOG("%p mergeable updating scroll offset from %s to %s\n", this,
-               ToString(Metrics().GetVisualScrollOffset()).c_str(),
-               ToString(scrollUpdate.GetDestination()).c_str());
-      relativeDelta =
-          Some(Metrics().ApplyAbsoluteScrollUpdateFrom(scrollUpdate).second);
-      Metrics().RecalculateLayoutViewportOffset();
-      scrollOffsetUpdated = true;
     } else {
       APZC_LOG("%p updating scroll offset from %s to %s\n", this,
                ToString(Metrics().GetVisualScrollOffset()).c_str(),
                ToString(scrollUpdate.GetDestination()).c_str());
-      auto [offsetChanged, _] =
-          Metrics().ApplyAbsoluteScrollUpdateFrom(scrollUpdate);
+      bool offsetChanged = Metrics().ApplyScrollUpdateFrom(scrollUpdate);
       Metrics().RecalculateLayoutViewportOffset();
 
       if (offsetChanged || scrollUpdate.GetMode() != ScrollMode::Instant ||
@@ -5788,6 +5777,15 @@ void AsyncPanZoomController::NotifyLayersUpdated(
     }
   }
 
+  if (aIsFirstPaint || needToReclampScroll) {
+    // The scrollable rect or composition bounds may have changed in a way that
+    // makes our local scroll offset out of bounds, so clamp it.
+    ClampAndSetVisualScrollOffset(Metrics().GetVisualScrollOffset());
+    for (auto& sampledState : mSampledState) {
+      sampledState.ClampVisualScrollOffset(Metrics());
+    }
+  }
+
   if (scrollOffsetUpdated) {
     for (auto& sampledState : mSampledState) {
       if (!didCancelAnimation && cumulativeRelativeDelta.isSome()) {