--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -3674,66 +3674,61 @@ nsDOMWindowUtils::GetOMTAStyle(Element* 
   RefPtr<nsROCSSPrimitiveValue> cssValue = nullptr;
   if (frame && nsLayoutUtils::AreAsyncAnimationsEnabled()) {
     RefPtr<LayerManager> widgetLayerManager;
     if (nsIWidget* widget = GetWidget()) {
       widgetLayerManager = widget->GetLayerManager();
     }
 
     if (aProperty.EqualsLiteral("opacity")) {
-      float value = 0;
-      bool hadAnimatedOpacity = false;
+      OMTAValue value;
 
       Layer* layer =
         FrameLayerBuilder::GetDedicatedLayer(frame, DisplayItemType::TYPE_OPACITY);
       if (layer) {
         ShadowLayerForwarder* forwarder = layer->Manager()->AsShadowForwarder();
         if (forwarder && forwarder->HasShadowManager()) {
           forwarder->GetShadowManager()->
-            SendGetAnimationOpacity(layer->GetCompositorAnimationsId(),
-                                    &value,
-                                    &hadAnimatedOpacity);
+            SendGetAnimationValue(layer->GetCompositorAnimationsId(), &value);
         }
       } else if (WebRenderBridgeChild* wrbc = GetWebRenderBridge()) {
         RefPtr<WebRenderAnimationData> animationData =
             GetWebRenderUserData<WebRenderAnimationData>(frame, (uint32_t)DisplayItemType::TYPE_OPACITY);
         if (animationData) {
-          wrbc->SendGetAnimationOpacity(
+          wrbc->SendGetAnimationValue(
               animationData->GetAnimationInfo().GetCompositorAnimationsId(),
-              &value,
-              &hadAnimatedOpacity);
+              &value);
         }
       }
-      if (hadAnimatedOpacity) {
+      if (value.type() == OMTAValue::Tfloat) {
         cssValue = new nsROCSSPrimitiveValue;
-        cssValue->SetNumber(value);
+        cssValue->SetNumber(value.get_float());
       }
     } else if (aProperty.EqualsLiteral("transform")) {
-      MaybeTransform transform;
+      OMTAValue value;
 
       Layer* layer =
         FrameLayerBuilder::GetDedicatedLayer(frame, DisplayItemType::TYPE_TRANSFORM);
       if (layer) {
         ShadowLayerForwarder* forwarder = layer->Manager()->AsShadowForwarder();
         if (forwarder && forwarder->HasShadowManager()) {
           forwarder->GetShadowManager()->
-            SendGetAnimationTransform(layer->GetCompositorAnimationsId(), &transform);
+            SendGetAnimationValue(layer->GetCompositorAnimationsId(), &value);
         }
       } else if (WebRenderBridgeChild* wrbc = GetWebRenderBridge()) {
         RefPtr<WebRenderAnimationData> animationData =
             GetWebRenderUserData<WebRenderAnimationData>(frame, (uint32_t)DisplayItemType::TYPE_TRANSFORM);
         if (animationData) {
-          wrbc->SendGetAnimationTransform(
+          wrbc->SendGetAnimationValue(
               animationData->GetAnimationInfo().GetCompositorAnimationsId(),
-              &transform);
+              &value);
         }
       }
-      if (transform.type() == MaybeTransform::TMatrix4x4) {
-        Matrix4x4 matrix = transform.get_Matrix4x4();
-        cssValue = nsComputedDOMStyle::MatrixToCSSValue(matrix);
+      if (value.type() == OMTAValue::TMatrix4x4) {
+        cssValue = nsComputedDOMStyle::MatrixToCSSValue(value.get_Matrix4x4());
       }
     }
   }
 
   if (cssValue) {
     nsString text;
     ErrorResult rv;
     cssValue->GetCssText(text, rv);

--- a/gfx/layers/AnimationHelper.cpp
+++ b/gfx/layers/AnimationHelper.cpp
@@ -80,16 +80,57 @@ CompositorAnimationStorage::GetAnimation
     double(scale) / double(nsDeviceContext::AppUnitsPerCSSPixel());
   transform._41 *= devPerCss;
   transform._42 *= devPerCss;
   transform._43 *= devPerCss;
 
   return Some(transform);
 }
 
+OMTAValue
+CompositorAnimationStorage::GetOMTAValue(const uint64_t& aId) const
+{
+  OMTAValue omtaValue = mozilla::null_t();
+  auto animatedValue = GetAnimatedValue(aId);
+  if (!animatedValue) {
+    return omtaValue;
+  }
+
+  switch (animatedValue->mType) {
+    case AnimatedValue::OPACITY:
+      omtaValue = animatedValue->mOpacity;
+      break;
+    case AnimatedValue::TRANSFORM: {
+      gfx::Matrix4x4 transform = animatedValue->mTransform.mFrameTransform;
+      const TransformData& data = animatedValue->mTransform.mData;
+      float scale = data.appUnitsPerDevPixel();
+      gfx::Point3D transformOrigin = data.transformOrigin();
+
+      // Undo the rebasing applied by
+      // nsDisplayTransform::GetResultingTransformMatrixInternal
+      transform.ChangeBasis(-transformOrigin);
+
+      // Convert to CSS pixels (this undoes the operations performed by
+      // nsStyleTransformMatrix::ProcessTranslatePart which is called from
+      // nsDisplayTransform::GetResultingTransformMatrix)
+      double devPerCss =
+        double(scale) / double(nsDeviceContext::AppUnitsPerCSSPixel());
+      transform._41 *= devPerCss;
+      transform._42 *= devPerCss;
+      transform._43 *= devPerCss;
+      omtaValue = transform;
+      break;
+    }
+    case AnimatedValue::NONE:
+      break;
+  }
+
+  return omtaValue;
+}
+
 void
 CompositorAnimationStorage::SetAnimatedValue(uint64_t aId,
                                              gfx::Matrix4x4&& aTransformInDevSpace,
                                              gfx::Matrix4x4&& aFrameTransform,
                                              const TransformData& aData)
 {
   MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
   auto count = mAnimatedValues.Count();

--- a/gfx/layers/AnimationHelper.h
+++ b/gfx/layers/AnimationHelper.h
@@ -141,16 +141,18 @@ public:
   /**
    * Like GetAnimatedValue(), but ensures the value is a transform and returns
    * the transform matrix if possible, or Nothing() otherwise. It also does
    * some post-processing on the transform matrix as well. See the comments
    * inside the function for details.
    */
   Maybe<gfx::Matrix4x4> GetAnimationTransform(const uint64_t& aId) const;
 
+  OMTAValue GetOMTAValue(const uint64_t& aId) const;
+
   /**
    * Return the iterator of animated value table
    */
   AnimatedValueTable::Iterator ConstAnimatedValueTableIter() const
   {
     return mAnimatedValues.ConstIter();
   }
 

--- a/gfx/layers/ipc/LayerTransactionParent.cpp
+++ b/gfx/layers/ipc/LayerTransactionParent.cpp
@@ -729,16 +729,39 @@ LayerTransactionParent::RecvGetAnimation
     *aTransform = *transform;
   } else {
     *aTransform = mozilla::void_t();
   }
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
+LayerTransactionParent::RecvGetAnimationValue(const uint64_t& aCompositorAnimationsId,
+                                              OMTAValue* aValue)
+{
+  if (mDestroyed || !mLayerManager || mLayerManager->IsDestroyed()) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+
+  // Make sure we apply the latest animation style or else we can end up with
+  // a race between when we temporarily clear the animation transform (in
+  // CompositorBridgeParent::SetShadowProperties) and when animation recalculates
+  // the value.
+  mCompositorBridge->ApplyAsyncProperties(
+    this, CompositorBridgeParentBase::TransformsToSkip::APZ);
+
+  if (!mAnimStorage) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+
+  *aValue = mAnimStorage->GetOMTAValue(aCompositorAnimationsId);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
 LayerTransactionParent::RecvGetTransform(const LayerHandle& aLayerHandle,
                                          MaybeTransform* aTransform)
 {
   if (mDestroyed || !mLayerManager || mLayerManager->IsDestroyed()) {
     return IPC_FAIL_NO_REASON(this);
   }
 
   Layer* layer = AsLayer(aLayerHandle);

--- a/gfx/layers/ipc/LayerTransactionParent.h
+++ b/gfx/layers/ipc/LayerTransactionParent.h
@@ -125,16 +125,18 @@ protected:
   mozilla::ipc::IPCResult RecvScheduleComposite() override;
   mozilla::ipc::IPCResult RecvSetTestSampleTime(const TimeStamp& aTime) override;
   mozilla::ipc::IPCResult RecvLeaveTestMode() override;
   mozilla::ipc::IPCResult RecvGetAnimationOpacity(const uint64_t& aCompositorAnimationsId,
                                                   float* aOpacity,
                                                   bool* aHasAnimationOpacity) override;
   mozilla::ipc::IPCResult RecvGetAnimationTransform(const uint64_t& aCompositorAnimationsId,
                                                     MaybeTransform* aTransform) override;
+  mozilla::ipc::IPCResult RecvGetAnimationValue(const uint64_t& aCompositorAnimationsId,
+                                                OMTAValue* aValue) override;
   mozilla::ipc::IPCResult RecvGetTransform(const LayerHandle& aHandle,
                                            MaybeTransform* aTransform) override;
   mozilla::ipc::IPCResult RecvSetAsyncScrollOffset(const FrameMetrics::ViewID& aId,
                                                    const float& aX, const float& aY) override;
   mozilla::ipc::IPCResult RecvSetAsyncZoom(const FrameMetrics::ViewID& aId,
                                            const float& aValue) override;
   mozilla::ipc::IPCResult RecvFlushApzRepaints() override;
   mozilla::ipc::IPCResult RecvGetAPZTestData(APZTestData* aOutData) override;

--- a/gfx/layers/ipc/LayersMessages.ipdlh
+++ b/gfx/layers/ipc/LayersMessages.ipdlh
@@ -565,10 +565,16 @@ struct TransactionInfo
   TimeStamp fwdTime;
 };
 
 union MaybeTransform {
   Matrix4x4;
   void_t;
 };
 
+union OMTAValue {
+  null_t;
+  float;
+  Matrix4x4;
+};
+
 } // namespace
 } // namespace

--- a/gfx/layers/ipc/PLayerTransaction.ipdl
+++ b/gfx/layers/ipc/PLayerTransaction.ipdl
@@ -11,16 +11,17 @@ include protocol PCompositorBridge;
 include protocol PRenderFrame;
 include protocol PTexture;
 
 include "mozilla/GfxMessageUtils.h";
 include "mozilla/layers/LayersMessageUtils.h";
 
 using struct mozilla::layers::TextureInfo from "mozilla/layers/CompositorTypes.h";
 using struct mozilla::void_t from "ipc/IPCMessageUtils.h";
+using struct mozilla::null_t from "ipc/IPCMessageUtils.h";
 using class mozilla::layers::APZTestData from "mozilla/layers/APZTestData.h";
 using mozilla::layers::FrameMetrics::ViewID from "FrameMetrics.h";
 using struct mozilla::layers::ScrollableLayerGuid from "FrameMetrics.h";
 using struct mozilla::layers::TextureFactoryIdentifier from "mozilla/layers/CompositorTypes.h";
 using mozilla::layers::LayersBackend from "mozilla/layers/LayersTypes.h";
 using mozilla::layers::LayerHandle from "mozilla/layers/LayersTypes.h";
 using mozilla::layers::CompositableHandle from "mozilla/layers/LayersTypes.h";
 using mozilla::layers::LayersObserverEpoch from "mozilla/layers/LayersTypes.h";
@@ -71,16 +72,19 @@ parent:
   // Testing APIs
 
   // Enter test mode, set the sample time to sampleTime, and resample
   // animations. sampleTime must not be null.
   sync SetTestSampleTime(TimeStamp sampleTime);
   // Leave test mode and resume normal compositing
   sync LeaveTestMode();
 
+  // Returns |OMTAValue| applied to the layer.
+  sync GetAnimationValue(uint64_t aCompositorAnimationId) returns (OMTAValue value);
+
   // Returns the value of the opacity applied to the layer by animation.
   // |hasAnimationOpacity| is true if the layer has an opacity value
   // specified by animation. If it's false, |opacity| value is indefinite.
   sync GetAnimationOpacity(uint64_t aCompositorAnimationsId) returns (float opacity,
                                                   bool hasAnimationOpacity);
 
   // Returns the value of the transform applied to the layer by animation after
   // factoring out translation components introduced to account for the offset

--- a/gfx/layers/ipc/PWebRenderBridge.ipdl
+++ b/gfx/layers/ipc/PWebRenderBridge.ipdl
@@ -65,16 +65,17 @@ parent:
   sync SyncWithCompositor();
 
   // These correspond exactly to the equivalent APIs in PLayerTransaction -
   // see those for documentation.
   async SetConfirmedTargetAPZC(uint64_t aInputBlockId, ScrollableLayerGuid[] aTargets);
   // More copied from PLayerTransaction, but these are only used for testing.
   sync SetTestSampleTime(TimeStamp sampleTime);
   sync LeaveTestMode();
+  sync GetAnimationValue(uint64_t aCompositorAnimationsId) returns (OMTAValue value);
   sync GetAnimationOpacity(uint64_t aCompositorAnimationsId) returns (float opacity,
                                                   bool hasAnimationOpacity);
   sync GetAnimationTransform(uint64_t aCompositorAnimationId) returns (MaybeTransform transform);
   sync SetAsyncScrollOffset(ViewID scrollId, float x, float y);
   sync SetAsyncZoom(ViewID scrollId, float zoom);
   async FlushApzRepaints();
   sync GetAPZTestData() returns (APZTestData data);
 

--- a/gfx/layers/wr/WebRenderBridgeParent.cpp
+++ b/gfx/layers/wr/WebRenderBridgeParent.cpp
@@ -1356,16 +1356,35 @@ WebRenderBridgeParent::RecvSetTestSample
 mozilla::ipc::IPCResult
 WebRenderBridgeParent::RecvLeaveTestMode()
 {
   mCompositorBridge->LeaveTestMode(GetLayersId());
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
+WebRenderBridgeParent::RecvGetAnimationValue(const uint64_t& aCompositorAnimationsId,
+                                             OMTAValue* aValue)
+{
+  if (mDestroyed) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+
+  MOZ_ASSERT(mAnimStorage);
+  if (RefPtr<WebRenderBridgeParent> root = GetRootWebRenderBridgeParent()) {
+    root->AdvanceAnimations();
+  } else {
+    AdvanceAnimations();
+  }
+
+  *aValue = mAnimStorage->GetOMTAValue(aCompositorAnimationsId);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
 WebRenderBridgeParent::RecvGetAnimationOpacity(const uint64_t& aCompositorAnimationsId,
                                                float* aOpacity,
                                                bool* aHasAnimationOpacity)
 {
   if (mDestroyed) {
     return IPC_FAIL_NO_REASON(this);
   }
 

--- a/gfx/layers/wr/WebRenderBridgeParent.h
+++ b/gfx/layers/wr/WebRenderBridgeParent.h
@@ -113,16 +113,18 @@ public:
   mozilla::ipc::IPCResult RecvCapture() override;
   mozilla::ipc::IPCResult RecvSyncWithCompositor() override;
 
   mozilla::ipc::IPCResult RecvSetConfirmedTargetAPZC(const uint64_t& aBlockId,
                                                      nsTArray<ScrollableLayerGuid>&& aTargets) override;
 
   mozilla::ipc::IPCResult RecvSetTestSampleTime(const TimeStamp& aTime) override;
   mozilla::ipc::IPCResult RecvLeaveTestMode() override;
+  mozilla::ipc::IPCResult RecvGetAnimationValue(const uint64_t& aCompositorAnimationsId,
+                                                OMTAValue* aValue) override;
   mozilla::ipc::IPCResult RecvGetAnimationOpacity(const uint64_t& aCompositorAnimationsId,
                                                   float* aOpacity,
                                                   bool* aHasAnimationOpacity) override;
   mozilla::ipc::IPCResult RecvGetAnimationTransform(const uint64_t& aCompositorAnimationsId,
                                                     MaybeTransform* aTransform) override;
   mozilla::ipc::IPCResult RecvSetAsyncScrollOffset(const FrameMetrics::ViewID& aScrollId,
                                                    const float& aX,
                                                    const float& aY) override;

--- a/ipc/ipdl/sync-messages.ini
+++ b/ipc/ipdl/sync-messages.ini
@@ -994,16 +994,18 @@ description =
 [PLayerTransaction::SetTestSampleTime]
 description =
 [PLayerTransaction::LeaveTestMode]
 description =
 [PLayerTransaction::GetAnimationOpacity]
 description =
 [PLayerTransaction::GetAnimationTransform]
 description =
+[PLayerTransaction::GetAnimationValue]
+description = test only
 [PLayerTransaction::GetTransform]
 description = test only
 [PLayerTransaction::SetAsyncScrollOffset]
 description =
 [PLayerTransaction::SetAsyncZoom]
 description =
 [PLayerTransaction::GetAPZTestData]
 description =
@@ -1020,16 +1022,18 @@ description =
 [PWebRenderBridge::Create]
 description =
 [PWebRenderBridge::GetSnapshot]
 description =
 [PWebRenderBridge::SetTestSampleTime]
 description = test only
 [PWebRenderBridge::LeaveTestMode]
 description = test only
+[PWebRenderBridge::GetAnimationValue]
+description = test only
 [PWebRenderBridge::GetAnimationOpacity]
 description = test only
 [PWebRenderBridge::GetAnimationTransform]
 description = test only
 [PWebRenderBridge::SetAsyncScrollOffset]
 description = test only
 [PWebRenderBridge::SetAsyncZoom]
 description = test only