Bug 1522724 - Add scroll update type for nsIDOMWindowUtils.scrollToVisual(). r=botond

Depends on D17582

Differential Revision: https://phabricator.services.mozilla.com/D17583

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

dom/base/nsDOMWindowUtils.cpp

@@ -1395,7 +1395,8 @@ nsDOMWindowUtils::GetScrollXYFloat(bool aFlushLayout, float* aScrollX,
 }
 
 NS_IMETHODIMP
-nsDOMWindowUtils::ScrollToVisual(float aOffsetX, float aOffsetY) {
+nsDOMWindowUtils::ScrollToVisual(float aOffsetX, float aOffsetY,
+                                 int32_t aUpdateType) {
   nsCOMPtr<Document> doc = GetDocument();
   NS_ENSURE_STATE(doc);
 
@@ -1405,12 +1406,20 @@ nsDOMWindowUtils::ScrollToVisual(float aOffsetX, float aOffsetY) {
   // This should only be called on the root content document.
   NS_ENSURE_TRUE(presContext->IsRootContentDocument(), NS_ERROR_INVALID_ARG);
 
-  // Use |eRestore| as the priority for now, as it's the conservative choice.
-  // If a JS call site needs higher priority, we can expose the update type
-  // as a parameter.
+  FrameMetrics::ScrollOffsetUpdateType updateType;
+  switch (aUpdateType) {
+    case UPDATE_TYPE_RESTORE:
+      updateType = FrameMetrics::eRestore;
+      break;
+    case UPDATE_TYPE_MAIN_THREAD:
+      updateType = FrameMetrics::eMainThread;
+      break;
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
   presContext->PresShell()->SetPendingVisualScrollUpdate(
-      CSSPoint::ToAppUnits(CSSPoint(aOffsetX, aOffsetY)),
-      FrameMetrics::eRestore);
+      CSSPoint::ToAppUnits(CSSPoint(aOffsetX, aOffsetY)), updateType);
 
   return NS_OK;
 }

dom/interfaces/base/nsIDOMWindowUtils.idl

@@ -839,7 +839,9 @@ interface nsIDOMWindowUtils : nsISupports {
    * SetPendingVisualViewportOffset(), and request APZ review if adding a new
    * call to this.
    */
-  void scrollToVisual(in float aOffsetX, in float aOffsetY);
+  const long UPDATE_TYPE_RESTORE = 0;
+  const long UPDATE_TYPE_MAIN_THREAD = 1;
+  void scrollToVisual(in float aOffsetX, in float aOffsetY, in long aUpdateType);
 
   /**
    * Returns the offset of the window's visual viewport relative to the

gfx/layers/apz/test/mochitest/helper_fullscreen.html

@@ -19,6 +19,8 @@
   <div style="background: red; width: 200%; height: 100px;">overflowed element</div>
   <div id="target" style="background: green; width: 100px; height: 100px;"></div>
   <script type="application/javascript">
+    const utils = SpecialPowers.getDOMWindowUtils(window);
+
     function waitForFullscreenChange() {
       return new Promise(resolve => {
         document.addEventListener("fullscreenchange", resolve);
@@ -34,7 +36,7 @@
          "The target element should have been fullscreen-ed");
 
       // Try to move rightward, but it should NOT happen.
-      SpecialPowers.getDOMWindowUtils(window).scrollToVisual(200, 0);
+      utils.scrollToVisual(200, 0, utils.UPDATE_TYPE_MAIN_THREAD);
 
       await waitUntilApzStable();
 

gfx/layers/apz/test/mochitest/helper_minimum_scale_1_0.html

@@ -20,8 +20,10 @@
   <div style="width: 200%; height: 200%; background-color: green"></div>
   <div style="width: 100%; height: 100%; background-color: blue"></div>
   <script type="application/javascript">
+    const utils = SpecialPowers.getDOMWindowUtils(window);
+
     async function test(testDriver) {
-      SpecialPowers.getDOMWindowUtils(window).scrollToVisual(100, 0);
+      utils.scrollToVisual(100, 0, utils.UPDATE_TYPE_MAIN_THREAD);
 
       const promiseForVisualViewportScroll = new Promise(resolve => {
         window.visualViewport.addEventListener("scroll", () => {