Bug 1617179 - Extract a helper method across WR and non-WR codepaths. r=botond

The operations of recording checkerboard events and advancing the animations
across all APZs are conceptually linked. This patch extracts a helper that
does these operations in a single function, that is then called from both
the WR and non-WR codepaths. This will allow us to expand this code a bit
without having to duplicate it in multiple places.

Differential Revision: https://phabricator.services.mozilla.com/D67374

--HG--
extra : moz-landing-system : lando

gfx/layers/apz/public/APZSampler.h

@@ -67,8 +67,7 @@ class APZSampler {
                           wr::RenderRoot aRenderRoot,
                           const wr::WrPipelineIdEpochs* aEpochsBeingRendered);
 
-  bool SampleAnimations(const LayerMetricsWrapper& aLayer,
-                        const TimeStamp& aSampleTime);
+  bool AdvanceAnimations(const TimeStamp& aSampleTime);
 
   /**
    * Compute the updated shadow transform for a scroll thumb layer that

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -788,8 +788,6 @@ void APZCTreeManager::SampleForWebRender(
                               apzc->GetGuid().mScrollId,
                               wr::ToLayoutPoint(asyncScrollDelta));
 
-    apzc->ReportCheckerboard(aSampleTime);
-
 #if defined(MOZ_WIDGET_ANDROID)
     // Send the root frame metrics to java through the UIController
     RefPtr<UiCompositorControllerParent> uiController =
@@ -866,15 +864,8 @@ void APZCTreeManager::SampleForWebRender(
   // sampling all async transforms, because AdvanceAnimations() updates
   // the effective scroll offset to the value it should have for the *next*
   // composite after this one (if the APZ frame delay is enabled).
-  bool activeAnimations = false;
-  for (const auto& mapping : mApzcMap) {
-    AsyncPanZoomController* apzc = mapping.second;
-    if (apzc->GetRenderRoot() != aRenderRoot) {
-      // If this APZC belongs to a different render root, skip over it
-      continue;
-    }
-    activeAnimations |= apzc->AdvanceAnimations(aSampleTime);
-  }
+  bool activeAnimations =
+      AdvanceAnimationsInternal(lock, Some(aRenderRoot), aSampleTime);
   if (activeAnimations) {
     RefPtr<CompositorController> controller;
     CompositorBridgeParent::CallWithIndirectShadowTree(
@@ -888,6 +879,28 @@ void APZCTreeManager::SampleForWebRender(
   }
 }
 
+bool APZCTreeManager::AdvanceAnimations(Maybe<wr::RenderRoot> aRenderRoot,
+                                        const TimeStamp& aSampleTime) {
+  MutexAutoLock lock(mMapLock);
+  return AdvanceAnimationsInternal(lock, std::move(aRenderRoot), aSampleTime);
+}
+
+bool APZCTreeManager::AdvanceAnimationsInternal(
+    const MutexAutoLock& aProofOfMapLock, Maybe<wr::RenderRoot> aRenderRoot,
+    const TimeStamp& aSampleTime) {
+  bool activeAnimations = false;
+  for (const auto& mapping : mApzcMap) {
+    AsyncPanZoomController* apzc = mapping.second;
+    if (aRenderRoot && apzc->GetRenderRoot() != *aRenderRoot) {
+      // If this APZC belongs to a different render root, skip over it
+      continue;
+    }
+    apzc->ReportCheckerboard(aSampleTime);
+    activeAnimations |= apzc->AdvanceAnimations(aSampleTime);
+  }
+  return activeAnimations;
+}
+
 // Compute the clip region to be used for a layer with an APZC. This function
 // is only called for layers which actually have scrollable metrics and an APZC.
 template <class ScrollNode>

gfx/layers/apz/src/APZCTreeManager.h

@@ -204,6 +204,14 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
                           wr::RenderRoot aRenderRoot,
                           const wr::WrPipelineIdEpochs* aEpochsBeingRendered);
 
+  /**
+   * Walk through all the APZCs and do the sampling steps needed when
+   * advancing to the next frame. The APZCs walked can be restricted to a
+   * specific render root by providing that as the first argument.
+   */
+  bool AdvanceAnimations(Maybe<wr::RenderRoot> aRenderRoot,
+                         const TimeStamp& aSampleTime);
+
   /**
    * Refer to the documentation of APZInputBridge::ReceiveInputEvent() and
    * APZEventResult.
@@ -743,6 +751,10 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
   static already_AddRefed<GeckoContentController> GetContentController(
       LayersId aLayersId);
 
+  bool AdvanceAnimationsInternal(const MutexAutoLock& aProofOfMapLock,
+                                 Maybe<wr::RenderRoot> aRenderRoot,
+                                 const TimeStamp& aSampleTime);
+
  protected:
   /* The input queue where input events are held until we know enough to
    * figure out where they're going. Protected so gtests can access it.

gfx/layers/apz/src/APZSampler.cpp

@@ -99,26 +99,10 @@ void APZSampler::SampleForWebRender(
   mApz->SampleForWebRender(aTxn, sampleTime, aRenderRoot, aEpochsBeingRendered);
 }
 
-bool APZSampler::SampleAnimations(const LayerMetricsWrapper& aLayer,
-                                  const TimeStamp& aSampleTime) {
+bool APZSampler::AdvanceAnimations(const TimeStamp& aSampleTime) {
   MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
   AssertOnSamplerThread();
-
-  // TODO: eventually we can drop the aLayer argument and just walk the APZ
-  // tree directly in mApz.
-
-  bool activeAnimations = false;
-
-  ForEachNodePostOrder<ForwardIterator>(
-      aLayer,
-      [&activeAnimations, &aSampleTime](LayerMetricsWrapper aLayerMetrics) {
-        if (AsyncPanZoomController* apzc = aLayerMetrics.GetApzc()) {
-          apzc->ReportCheckerboard(aSampleTime);
-          activeAnimations |= apzc->AdvanceAnimations(aSampleTime);
-        }
-      });
-
-  return activeAnimations;
+  return mApz->AdvanceAnimations(Nothing(), aSampleTime);
 }
 
 LayerToParentLayerMatrix4x4 APZSampler::ComputeTransformForScrollThumb(

gfx/layers/composite/AsyncCompositionManager.cpp

@@ -1490,8 +1490,7 @@ bool AsyncCompositionManager::TransformShadowTree(
 
     bool apzAnimating = false;
     if (RefPtr<APZSampler> apz = mCompositorBridge->GetAPZSampler()) {
-      apzAnimating =
-          apz->SampleAnimations(LayerMetricsWrapper(root), nextFrame);
+      apzAnimating = apz->AdvanceAnimations(nextFrame);
     }
     wantNextFrame |= apzAnimating;
   }