fixup! Dispel the myth that enclosingLayer can return zero

According from the commit messages of previous commit, enclosingLayer() cannot be nullptr, but it removed a check for container() returning nullptr actually. We need to check nullptr before using it in LayoutObject::ComputeLayerHitTestRects(). This patch is re-organizing the existing conditions to remove potential risk factors. Original patch = https://codereview.chromium.org/215843002 BUG=752371 Change-Id: I29a1d2d98f7daa200bf3f001e430d8e3aa9f38f3 Reviewed-on: https://chromium-review.googlesource.com/587691 Reviewed-by: Stephen Chenney <[email protected]> Commit-Queue: Stephen Chenney <[email protected]> Cr-Commit-Position: refs/heads/master@{#495222}
feiyue1206 · Aug 17, 2017 · 219e1da · 219e1da
1 parent 8451e2e
commit 219e1da
Showing 1 changed file with 13 additions and 10 deletions.
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -2357,16 +2357,19 @@ void LayoutObject::ComputeLayerHitTestRects(
 
   if (!HasLayer()) {
     LayoutObject* container = this->Container();
-    current_layer = container->EnclosingLayer();
-    if (container && current_layer->GetLayoutObject() != container) {
-      layer_offset.Move(container->OffsetFromAncestorContainer(
-          &current_layer->GetLayoutObject()));
-      // If the layer itself is scrolled, we have to undo the subtraction of its
-      // scroll offset since we want the offset relative to the scrolling
-      // content, not the element itself.
-      if (current_layer->GetLayoutObject().HasOverflowClip())
-        layer_offset.Move(
-            current_layer->GetLayoutBox()->ScrolledContentOffset());
+    if (container) {
+      current_layer = container->EnclosingLayer();
+      if (current_layer->GetLayoutObject() != container) {
+        layer_offset.Move(container->OffsetFromAncestorContainer(
+            &current_layer->GetLayoutObject()));
+        // If the layer itself is scrolled, we have to undo the subtraction of
+        // its scroll offset since we want the offset relative to the scrolling
+        // content, not the element itself.
+        if (current_layer->GetLayoutObject().HasOverflowClip()) {
+          layer_offset.Move(
+              current_layer->GetLayoutBox()->ScrolledContentOffset());
+        }
+      }
     }
   }