Bug 1866939 - Offset the in-process root frame scroll position layout in nsDOMWindowUtils::ZoomToFocusedInput(). r=botond

And complement it in APZCTreeManager::ConvertRectInApzcToRoot in the case of
the given APZC is the root content one.

Depends on D197259

Differential Revision: https://phabricator.services.mozilla.com/D197260

dom/base/nsDOMWindowUtils.cpp

@@ -3106,6 +3106,8 @@ nsDOMWindowUtils::ZoomToFocusedInput() {
     return NS_OK;
   }
 
+  bounds -= CSSPoint::FromAppUnits(rootScrollFrame->GetScrollPosition());
+
   bool waitForRefresh = false;
   for (nsIScrollableFrame* scrollAncestor :
        CollectScrollableAncestors(element->GetPrimaryFrame())) {

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -3363,10 +3363,14 @@ CSSRect APZCTreeManager::ConvertRectInApzcToRoot(AsyncPanZoomController* aApzc,
                                                  const CSSRect& aRect) const {
   MOZ_ASSERT(aApzc->IsRootForLayersId());
   RefPtr<AsyncPanZoomController> rootContentApzc = FindZoomableApzc(aApzc);
-  if (!rootContentApzc || rootContentApzc == aApzc) {
+  if (!rootContentApzc) {
     return aRect;
   }
 
+  if (rootContentApzc == aApzc) {
+    return aRect + rootContentApzc->GetLayoutScrollOffset();
+  }
+
   return GetOopifToRootContentTransform(aApzc).TransformBounds(aRect);
 }
 

gfx/layers/apz/test/mochitest/helper_zoomToFocusedInput_iframe-2.html

@@ -36,13 +36,14 @@ async function setupIframe(aURL) {
   });
 }
 
+let initial_resolution;
 async function test(aTestFile) {
   let iframeURL = SimpleTest.getTestFileURL(aTestFile);
 
   // Load the test document in the same origin.
   await setupIframe(iframeURL);
 
-  let initial_resolution = await getResolution();
+  initial_resolution = await getResolution();
   ok(initial_resolution > 0,
      "The initial_resolution is " + initial_resolution + ", which is some sane value");
 
@@ -88,6 +89,12 @@ async function moveIframe() {
 }
 
 waitUntilApzStable()
+.then(async () => test("helper_zoomToFocusedInput_iframe_subframe.html?margin-top=200vh"))
+.then(async () => {
+  // Reset the scale to the initial value.
+  SpecialPowers.DOMWindowUtils.setResolutionAndScaleTo(initial_resolution);
+  await promiseApzFlushedRepaints();
+})
 // A test case where the layout scroll offset isn't zero.
 .then(async () => moveIframe())
 .then(async () => test("helper_zoomToFocusedInput_iframe_subframe.html"))

widget/nsIWidget.h

@@ -2032,6 +2032,11 @@ class nsIWidget : public nsISupports {
   virtual TextEventDispatcherListener*
   GetNativeTextEventDispatcherListener() = 0;
 
+  /**
+   * Trigger an animation to zoom to the given |aRect|.
+   * |aRect| should be relative to the layout viewport of the widget's root
+   * document
+   */
   virtual void ZoomToRect(const uint32_t& aPresShellId,
                           const ScrollableLayerGuid::ViewID& aViewId,
                           const CSSRect& aRect, const uint32_t& aFlags) = 0;