diff --git a/widget/InputData.cpp b/widget/InputData.cpp
index 0d7e701f0396..36ba907c53a6 100644
--- a/widget/InputData.cpp
+++ b/widget/InputData.cpp
@@ -146,8 +146,11 @@ void MultiTouchInput::Translate(const ScreenPoint& aTranslation) {
   const int32_t xTranslation = (int32_t)(aTranslation.x + 0.5f);
   const int32_t yTranslation = (int32_t)(aTranslation.y + 0.5f);
 
-  for (auto iter = mTouches.begin(); iter != mTouches.end(); iter++) {
-    iter->mScreenPoint.MoveBy(xTranslation, yTranslation);
+  for (auto& touchData : mTouches) {
+    for (auto& historicalData : touchData.mHistoricalData) {
+      historicalData.mScreenPoint.MoveBy(xTranslation, yTranslation);
+    }
+    touchData.mScreenPoint.MoveBy(xTranslation, yTranslation);
   }
 }
 
@@ -205,13 +208,21 @@ int32_t MultiTouchInput::IndexOfTouch(int32_t aTouchIdentifier) {
 
 bool MultiTouchInput::TransformToLocal(
     const ScreenToParentLayerMatrix4x4& aTransform) {
-  for (size_t i = 0; i < mTouches.Length(); i++) {
+  for (auto& touchData : mTouches) {
+    for (auto& historicalData : touchData.mHistoricalData) {
+      Maybe<ParentLayerIntPoint> historicalPoint =
+          UntransformBy(aTransform, historicalData.mScreenPoint);
+      if (!historicalPoint) {
+        return false;
+      }
+      historicalData.mLocalScreenPoint = *historicalPoint;
+    }
     Maybe<ParentLayerIntPoint> point =
-        UntransformBy(aTransform, mTouches[i].mScreenPoint);
+        UntransformBy(aTransform, touchData.mScreenPoint);
     if (!point) {
       return false;
     }
-    mTouches[i].mLocalScreenPoint = *point;
+    touchData.mLocalScreenPoint = *point;
   }
   return true;
 }
diff --git a/widget/InputData.h b/widget/InputData.h
index 4cbbd9e41aea..dc86550e05fa 100644
--- a/widget/InputData.h
+++ b/widget/InputData.h
@@ -149,6 +149,28 @@ class SingleTouchData {
   // Warning, this class is serialized and sent over IPC. Any change to its
   // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
 
+  // Historical data of this touch, which  was coalesced into this event.
+  // Touch event coalescing can happen at the system level when the touch
+  // screen's sampling frequency is higher than the vsync rate, or when the
+  // UI thread is busy. When multiple "samples" of touch data are coalesced into
+  // one touch event, the touch event's regular position information is the
+  // information from the last sample. And the previous, "coalesced-away"
+  // samples are stored in mHistoricalData.
+
+  struct HistoricalTouchData {
+    // The timestamp at which the information in this "sample" was originally
+    // sampled.
+    TimeStamp mTimeStamp;
+
+    // The touch data of this historical sample.
+    ScreenIntPoint mScreenPoint;
+    ParentLayerPoint mLocalScreenPoint;
+    ScreenSize mRadius;
+    float mRotationAngle = 0.0f;
+    float mForce = 0.0f;
+  };
+  CopyableTArray<HistoricalTouchData> mHistoricalData;
+
   // A unique number assigned to each SingleTouchData within a MultiTouchInput
   // so that they can be easily distinguished when handling a touch
   // start/move/end.
diff --git a/widget/nsGUIEventIPC.h b/widget/nsGUIEventIPC.h
index c41fbdb4625f..4e88abbc6b66 100644
--- a/widget/nsGUIEventIPC.h
+++ b/widget/nsGUIEventIPC.h
@@ -1124,11 +1124,36 @@ struct ParamTraits<mozilla::InputData> {
   }
 };
 
+template <>
+struct ParamTraits<mozilla::SingleTouchData::HistoricalTouchData> {
+  typedef mozilla::SingleTouchData::HistoricalTouchData paramType;
+
+  static void Write(Message* aMsg, const paramType& aParam) {
+    WriteParam(aMsg, aParam.mTimeStamp);
+    WriteParam(aMsg, aParam.mScreenPoint);
+    WriteParam(aMsg, aParam.mLocalScreenPoint);
+    WriteParam(aMsg, aParam.mRadius);
+    WriteParam(aMsg, aParam.mRotationAngle);
+    WriteParam(aMsg, aParam.mForce);
+  }
+
+  static bool Read(const Message* aMsg, PickleIterator* aIter,
+                   paramType* aResult) {
+    return (ReadParam(aMsg, aIter, &aResult->mTimeStamp) &&
+            ReadParam(aMsg, aIter, &aResult->mScreenPoint) &&
+            ReadParam(aMsg, aIter, &aResult->mLocalScreenPoint) &&
+            ReadParam(aMsg, aIter, &aResult->mRadius) &&
+            ReadParam(aMsg, aIter, &aResult->mRotationAngle) &&
+            ReadParam(aMsg, aIter, &aResult->mForce));
+  }
+};
+
 template <>
 struct ParamTraits<mozilla::SingleTouchData> {
   typedef mozilla::SingleTouchData paramType;
 
   static void Write(Message* aMsg, const paramType& aParam) {
+    WriteParam(aMsg, aParam.mHistoricalData);
     WriteParam(aMsg, aParam.mIdentifier);
     WriteParam(aMsg, aParam.mScreenPoint);
     WriteParam(aMsg, aParam.mLocalScreenPoint);
@@ -1139,7 +1164,8 @@ struct ParamTraits<mozilla::SingleTouchData> {
 
   static bool Read(const Message* aMsg, PickleIterator* aIter,
                    paramType* aResult) {
-    return (ReadParam(aMsg, aIter, &aResult->mIdentifier) &&
+    return (ReadParam(aMsg, aIter, &aResult->mHistoricalData) &&
+            ReadParam(aMsg, aIter, &aResult->mIdentifier) &&
             ReadParam(aMsg, aIter, &aResult->mScreenPoint) &&
             ReadParam(aMsg, aIter, &aResult->mLocalScreenPoint) &&
             ReadParam(aMsg, aIter, &aResult->mRadius) &&