Bug 1627737 - Add `mTargetIsRoot` to `APZEventResult` r=botond

This allows us to determine if the event was handled in the
toplevel frame or not.

Differential Revision: https://phabricator.services.mozilla.com/D69871

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

gfx/layers/apz/public/APZInputBridge.h

@@ -56,6 +56,10 @@ struct APZEventResult {
    * The guid of the APZC this event was delivered to.
    */
   ScrollableLayerGuid mTargetGuid;
+  /**
+   * Whether or not mTargetGuid refers to the root content APZC
+   */
+  bool mTargetIsRoot;
   /**
    * If this event started or was added to an input block, the id of that
    * input block, otherwise InputBlockState::NO_BLOCK_ID.

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -1581,6 +1581,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
 
         // Update the out-parameters so they are what the caller expects.
         hit.mTargetApzc->GetGuid(&result.mTargetGuid);
+        result.mTargetIsRoot = hit.mTargetApzc->IsRootContent();
 
         if (!hitScrollbar) {
           // The input was not targeted at a scrollbar, so we untransform it
@@ -1665,6 +1666,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
 
         // Update the out-parameters so they are what the caller expects.
         hit.mTargetApzc->GetGuid(&result.mTargetGuid);
+        result.mTargetIsRoot = hit.mTargetApzc->IsRootContent();
         wheelInput.mOrigin = *untransformedOrigin;
       }
       break;
@@ -1723,6 +1725,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
 
         // Update the out-parameters so they are what the caller expects.
         hit.mTargetApzc->GetGuid(&result.mTargetGuid);
+        result.mTargetIsRoot = hit.mTargetApzc->IsRootContent();
         panInput.mPanStartPoint = *untransformedStartPoint;
         panInput.mPanDisplacement = *untransformedDisplacement;
 
@@ -1762,6 +1765,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
 
         // Update the out-parameters so they are what the caller expects.
         hit.mTargetApzc->GetGuid(&result.mTargetGuid);
+        result.mTargetIsRoot = hit.mTargetApzc->IsRootContent();
         pinchInput.mFocusPoint = *untransformedFocusPoint;
       }
       break;
@@ -1791,6 +1795,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
 
         // Update the out-parameters so they are what the caller expects.
         hit.mTargetApzc->GetGuid(&result.mTargetGuid);
+        result.mTargetIsRoot = hit.mTargetApzc->IsRootContent();
         tapInput.mPoint = *untransformedPoint;
       }
       break;
@@ -2071,6 +2076,7 @@ APZEventResult APZCTreeManager::ProcessTouchInput(MultiTouchInput& aInput) {
       MOZ_ASSERT(mHitResultForInputBlock != CompositorHitTestInvisibleToHit);
 
       mApzcForInputBlock->GetGuid(&result.mTargetGuid);
+      result.mTargetIsRoot = mApzcForInputBlock->IsRootContent();
       result.mStatus = mInputQueue->ReceiveInputEvent(
           mApzcForInputBlock, TargetConfirmationFlags{mHitResultForInputBlock},
           aInput, &result.mInputBlockId,
@@ -2175,6 +2181,7 @@ APZEventResult APZCTreeManager::ProcessTouchInputForScrollbarDrag(
   }
 
   mApzcForInputBlock->GetGuid(&result.mTargetGuid);
+  result.mTargetIsRoot = mApzcForInputBlock->IsRootContent();
 
   // Since the input was targeted at a scrollbar:
   //    - The original touch event (which will be sent on to content) will

gfx/layers/apz/src/APZInputBridge.cpp

@@ -25,6 +25,7 @@ namespace layers {
 
 APZEventResult::APZEventResult()
     : mStatus(nsEventStatus_eIgnore),
+      mTargetIsRoot(false),
       mInputBlockId(InputBlockState::NO_BLOCK_ID),
       mHitRegionWithApzAwareListeners(false) {}
 

gfx/layers/ipc/LayersMessageUtils.h

@@ -545,6 +545,7 @@ struct ParamTraits<mozilla::layers::APZEventResult> {
     WriteParam(aMsg, aParam.mTargetGuid);
     WriteParam(aMsg, aParam.mInputBlockId);
     WriteParam(aMsg, aParam.mHitRegionWithApzAwareListeners);
+    WriteParam(aMsg, aParam.mTargetIsRoot);
   }
 
   static bool Read(const Message* aMsg, PickleIterator* aIter,
@@ -552,7 +553,8 @@ struct ParamTraits<mozilla::layers::APZEventResult> {
     return (ReadParam(aMsg, aIter, &aResult->mStatus) &&
             ReadParam(aMsg, aIter, &aResult->mTargetGuid) &&
             ReadParam(aMsg, aIter, &aResult->mInputBlockId) &&
-            ReadParam(aMsg, aIter, &aResult->mHitRegionWithApzAwareListeners));
+            ReadParam(aMsg, aIter, &aResult->mHitRegionWithApzAwareListeners) &&
+            ReadParam(aMsg, aIter, &aResult->mTargetIsRoot));
   }
 };