Revert "Avoid crashing in cc::CalculateDrawPropertiesInternal"

This reverts commit a8177a9cd2.

Reason for revert: Root cause has been fixed.

Original change's description:
> Avoid crashing in cc::CalculateDrawPropertiesInternal
> 
> Might lead to correctness bugs, but that is (likely) better than crashing.
> This code is soon to be replaced by BlinkGenPropertyTree, so this fix
> should be short-lived.
> 
> Bug: 939342
> Change-Id: Ia14b31420a1a78e738036a3d2c6bff4d3b46ec0f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1554731
> Reviewed-by: weiliangc <weiliangc@chromium.org>
> Commit-Queue: Andrew Grieve <agrieve@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#648757}

TBR=danakj@chromium.org,weiliangc@chromium.org,agrieve@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 939342
Change-Id: If4ef9562c345d89ed4ae43d8e9a1bbc4c3dc0952
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1588703
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654955}

cc/trees/layer_tree_host_common.cc

@@ -326,23 +326,17 @@ static bool SkipForInvertibility(const LayerImpl* layer,
   bool non_root_copy_request =
       effect_node->closest_ancestor_with_copy_request_id >
       EffectTree::kContentsRootNodeId;
+  gfx::Transform from_target;
   // If there is a copy request, we check the invertibility of the transform
   // between the node corresponding to the layer and the node corresponding to
   // the copy request. Otherwise, we are interested in the invertibility of
   // screen space transform which is already cached on the transform node.
-  if (non_root_copy_request) {
-    // Null check is a temporary fix for crasher: https://crbug.com/939342
-    if (effect_node == nullptr)
-      return false;
-    gfx::Transform from_target;
-    return !property_trees->GetFromTarget(
-        layer->transform_tree_index(),
-        effect_node->closest_ancestor_with_copy_request_id, &from_target);
-  }
-  // Null check is a temporary fix for crasher: https://crbug.com/939342
-  if (transform_node == nullptr)
-    return false;
-  return !transform_node->ancestors_are_invertible;
+  return non_root_copy_request
+             ? !property_trees->GetFromTarget(
+                   layer->transform_tree_index(),
+                   effect_node->closest_ancestor_with_copy_request_id,
+                   &from_target)
+             : !transform_node->ancestors_are_invertible;
 }
 
 static void ComputeInitialRenderSurfaceList(