Bug 1721601. Move "zoom in if can't zoom out" from being a flag to part of ZoomTarget for AsyncPanZoomController::ZoomToRect. r=botond

Instead of passing this flag all of the time for double taps we want to decide to do this or not in CalculateRectToZoomTo. Moving it into ZoomTarget seems like a good way to do this (which is done in the next patch).

Differential Revision: https://phabricator.services.mozilla.com/D128435

dom/ipc/BrowserChild.cpp

@@ -1432,7 +1432,8 @@ void BrowserChild::HandleDoubleTap(const CSSPoint& aPoint,
       mApzcTreeManager) {
     ScrollableLayerGuid guid(mLayersId, presShellId, viewId);
 
-    mApzcTreeManager->ZoomToRect(guid, zoomTarget, ZOOM_IN_IF_CANT_ZOOM_OUT);
+    mApzcTreeManager->ZoomToRect(guid, zoomTarget,
+                                 ZoomToRectBehavior::DEFAULT_BEHAVIOR);
   }
 }
 
@@ -1535,7 +1536,7 @@ void BrowserChild::ZoomToRect(const uint32_t& aPresShellId,
   ScrollableLayerGuid guid(mLayersId, aPresShellId, aViewId);
 
   if (mApzcTreeManager) {
-    mApzcTreeManager->ZoomToRect(guid, ZoomTarget{aRect, Nothing()}, aFlags);
+    mApzcTreeManager->ZoomToRect(guid, ZoomTarget{aRect}, aFlags);
   }
 }
 

gfx/layers/apz/public/IAPZCTreeManager.h

@@ -37,9 +37,6 @@ enum ZoomToRectBehavior : uint32_t {
   DISABLE_ZOOM_OUT = 1 << 0,
   PAN_INTO_VIEW_ONLY = 1 << 1,
   ONLY_ZOOM_TO_DEFAULT_SCALE = 1 << 2,
-  // If we are asked to zoom out but cannot (due to zoom constraints, etc), then
-  // zoom in some small amount to provide feedback to the user.
-  ZOOM_IN_IF_CANT_ZOOM_OUT = 1 << 3
 };
 
 class AsyncDragMetrics;

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -5483,19 +5483,19 @@ void AsyncPanZoomController::ZoomToRect(const ZoomTarget& aZoomTarget,
     // 2. currentZoom is equal to mZoomConstraints.mMaxZoom and user still
     // double-tapping it
     // Treat these cases as a request to zoom out as much as possible
-    // unless we were passed the ZOOM_IN_IF_CANT_ZOOM_OUT flag and currentZoom
+    // unless cantZoomOutBehavior == ZoomIn and currentZoom
     // is equal to localMinZoom and user still double-tapping it, then try to
     // zoom in a small amount to provide feedback to the user.
     bool zoomOut = false;
     // True if we are already zoomed out and we are asked to either stay there
-    // or zoom out more and the ZOOM_IN_IF_CANT_ZOOM_OUT flag was passed.
+    // or zoom out more and cantZoomOutBehavior == ZoomIn.
     bool zoomInDefaultAmount = false;
     if (aFlags & DISABLE_ZOOM_OUT) {
       zoomOut = false;
     } else {
       if (rect.IsEmpty()) {
         if (currentZoom == localMinZoom &&
-            (aFlags & ZOOM_IN_IF_CANT_ZOOM_OUT) &&
+            aZoomTarget.cantZoomOutBehavior == CantZoomOutBehavior::ZoomIn &&
             (defaultZoomInAmount != 1.f)) {
           zoomInDefaultAmount = true;
         } else {
@@ -5508,7 +5508,8 @@ void AsyncPanZoomController::ZoomToRect(const ZoomTarget& aZoomTarget,
 
     // already at min zoom and asked to zoom out further
     if (!zoomOut && currentZoom == localMinZoom && targetZoom <= localMinZoom &&
-        (aFlags & ZOOM_IN_IF_CANT_ZOOM_OUT) && (defaultZoomInAmount != 1.f)) {
+        aZoomTarget.cantZoomOutBehavior == CantZoomOutBehavior::ZoomIn &&
+        (defaultZoomInAmount != 1.f)) {
       zoomInDefaultAmount = true;
     }
     MOZ_ASSERT(!(zoomInDefaultAmount && zoomOut));

gfx/layers/apz/test/gtest/TestBasic.cpp

@@ -380,7 +380,7 @@ TEST_F(APZCBasicTester, ZoomAndScrollableRectChangeAfterZoomChange) {
   MakeApzcZoomable();
 
   // Zoom to right side.
-  ZoomTarget zoomTarget{CSSRect(75, 25, 25, 25), Nothing()};
+  ZoomTarget zoomTarget{CSSRect(75, 25, 25, 25)};
   apzc->ZoomToRect(zoomTarget, 0);
 
   // Run the animation to completion, should take 250ms/16.67ms = 15 frames, but
@@ -392,7 +392,7 @@ TEST_F(APZCBasicTester, ZoomAndScrollableRectChangeAfterZoomChange) {
   EXPECT_FALSE(apzc->IsAsyncZooming());
 
   // Zoom out.
-  ZoomTarget zoomTarget2{CSSRect(0, 0, 100, 100), Nothing()};
+  ZoomTarget zoomTarget2{CSSRect(0, 0, 100, 100)};
   apzc->ZoomToRect(zoomTarget2, 0);
 
   // Run the animation a few times to get it going.
@@ -449,7 +449,7 @@ TEST_F(APZCBasicTester, ZoomToRectAndCompositionBoundsChange) {
   MakeApzcZoomable();
 
   // Start a zoom to a rect.
-  ZoomTarget zoomTarget{CSSRect(25, 25, 25, 25), Nothing()};
+  ZoomTarget zoomTarget{CSSRect(25, 25, 25, 25)};
   apzc->ZoomToRect(zoomTarget, 0);
 
   // Run the animation a few times to get it going.

gfx/layers/apz/util/ChromeProcessController.cpp

@@ -149,7 +149,7 @@ void ChromeProcessController::HandleDoubleTap(
             "IAPZCTreeManager::ZoomToRect", mAPZCTreeManager,
             &IAPZCTreeManager::ZoomToRect,
             ScrollableLayerGuid(aGuid.mLayersId, presShellId, viewId),
-            zoomTarget, ZoomToRectBehavior::ZOOM_IN_IF_CANT_ZOOM_OUT));
+            zoomTarget, ZoomToRectBehavior::DEFAULT_BEHAVIOR));
   }
 }
 

gfx/layers/apz/util/DoubleTapToZoom.cpp

@@ -206,13 +206,13 @@ ZoomTarget CalculateRectToZoomTo(
 
   RefPtr<PresShell> presShell = aRootContentDocument->GetPresShell();
   if (!presShell) {
-    return ZoomTarget{zoomOut};
+    return ZoomTarget{zoomOut, CantZoomOutBehavior::ZoomIn};
   }
 
   nsIScrollableFrame* rootScrollFrame =
       presShell->GetRootScrollFrameAsScrollable();
   if (!rootScrollFrame) {
-    return ZoomTarget{zoomOut};
+    return ZoomTarget{zoomOut, CantZoomOutBehavior::ZoomIn};
   }
 
   CSSPoint documentRelativePoint =
@@ -222,7 +222,8 @@ ZoomTarget CalculateRectToZoomTo(
 
   nsCOMPtr<dom::Element> element = ElementFromPoint(presShell, aPoint);
   if (!element) {
-    return ZoomTarget{zoomOut, Nothing(), Some(documentRelativePoint)};
+    return ZoomTarget{zoomOut, CantZoomOutBehavior::ZoomIn, Nothing(),
+                      Some(documentRelativePoint)};
   }
 
   FrameMetrics metrics =
@@ -234,7 +235,8 @@ ZoomTarget CalculateRectToZoomTo(
   }
 
   if (!element) {
-    return ZoomTarget{zoomOut, Nothing(), Some(documentRelativePoint)};
+    return ZoomTarget{zoomOut, CantZoomOutBehavior::ZoomIn, Nothing(),
+                      Some(documentRelativePoint)};
   }
 
   CSSPoint visualScrollOffset = metrics.GetVisualScrollOffset();
@@ -336,7 +338,8 @@ ZoomTarget CalculateRectToZoomTo(
   // If the rect is already taking up most of the visible area and is
   // stretching the width of the page, then we want to zoom out instead.
   if (RectHasAlmostSameZoomLevel(rect, compositedArea)) {
-    return ZoomTarget{zoomOut, Nothing(), Some(documentRelativePoint)};
+    return ZoomTarget{zoomOut, CantZoomOutBehavior::ZoomIn, Nothing(),
+                      Some(documentRelativePoint)};
   }
 
   elementBoundingRect = AddHMargin(elementBoundingRect, margin, metrics);
@@ -348,8 +351,8 @@ ZoomTarget CalculateRectToZoomTo(
 
   rect.Round();
   elementBoundingRect.Round();
-  return ZoomTarget{rect, Some(elementBoundingRect),
-                    Some(documentRelativePoint)};
+  return ZoomTarget{rect, CantZoomOutBehavior::ZoomIn,
+                    Some(elementBoundingRect), Some(documentRelativePoint)};
 }
 
 }  // namespace layers

gfx/layers/apz/util/DoubleTapToZoom.h

@@ -19,11 +19,17 @@ class Document;
 
 namespace layers {
 
+enum class CantZoomOutBehavior : int8_t { Nothing = 0, ZoomIn };
+
 struct ZoomTarget {
   // The preferred target rect that we'd like to zoom in on, if possible. An
   // empty rect means the browser should zoom out.
   CSSRect targetRect;
 
+  // If we are asked to zoom out but cannot (due to zoom constraints, etc), then
+  // zoom in some small amount to provide feedback to the user.
+  CantZoomOutBehavior cantZoomOutBehavior = CantZoomOutBehavior::Nothing;
+
   // If zooming all the way in on |targetRect| is not possible (for example, due
   // to a max zoom constraint), |elementBoundingRect| may be used to inform a
   // more optimal target scroll position (for example, we may try to maximize

gfx/layers/ipc/LayersMessageUtils.h

@@ -987,12 +987,20 @@ struct ParamTraits<mozilla::RayReferenceData> {
   }
 };
 
+template <>
+struct ParamTraits<mozilla::layers::CantZoomOutBehavior>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::layers::CantZoomOutBehavior,
+          mozilla::layers::CantZoomOutBehavior::Nothing,
+          mozilla::layers::CantZoomOutBehavior::ZoomIn> {};
+
 template <>
 struct ParamTraits<mozilla::layers::ZoomTarget> {
   typedef mozilla::layers::ZoomTarget paramType;
 
   static void Write(Message* aMsg, const paramType& aParam) {
     WriteParam(aMsg, aParam.targetRect);
+    WriteParam(aMsg, aParam.cantZoomOutBehavior);
     WriteParam(aMsg, aParam.elementBoundingRect);
     WriteParam(aMsg, aParam.documentRelativePointerPosition);
   }
@@ -1000,6 +1008,7 @@ struct ParamTraits<mozilla::layers::ZoomTarget> {
   static bool Read(const Message* aMsg, PickleIterator* aIter,
                    paramType* aResult) {
     return (ReadParam(aMsg, aIter, &aResult->targetRect) &&
+            ReadParam(aMsg, aIter, &aResult->cantZoomOutBehavior) &&
             ReadParam(aMsg, aIter, &aResult->elementBoundingRect) &&
             ReadParam(aMsg, aIter, &aResult->documentRelativePointerPosition));
   }

widget/nsBaseWidget.cpp

@@ -1869,7 +1869,7 @@ void nsBaseWidget::ZoomToRect(const uint32_t& aPresShellId,
           "layers::IAPZCTreeManager::ZoomToRect", mAPZC,
           &IAPZCTreeManager::ZoomToRect,
           ScrollableLayerGuid(layerId, aPresShellId, aViewId),
-          ZoomTarget{aRect, Nothing()}, aFlags));
+          ZoomTarget{aRect}, aFlags));
 }
 
 #ifdef ACCESSIBILITY