Revert "Add CHECKs to debug crash"

This reverts commit ffff10c5.

Reason for revert: Temporary CL served it's purpose. ScrollNodes marked as inner_viewport aren't the same as InnerViewportScrollNode.

Original change's description:
> Add CHECKs to debug crash
> 
> It looks like this crashes because of a null outer viewport scroll node.
> That should never happen here because we have an inner viewport scroll
> node.
> 
> There's a few ways this could be going wrong:
> 
> - A ScrollNode is marked as the inner scroll node even though it wasn't
>   registered as one in viewport_property_ids_
> - The ScrollNode doesn't exist in the property tree even though it was
>   registered.
> - We're getting this bad combination from Blink.
> 
> I've turned a few DCHECKs into release CHECKs to narrow down which of
> these it might be.
> 
> Bug: 1037759
> Change-Id: I972582da6e18725557859063da0889d465063c77
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1981268
> Commit-Queue: David Bokan <bokan@chromium.org>
> Auto-Submit: David Bokan <bokan@chromium.org>
> Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#728220}

TBR=wangxianzhu@chromium.org,bokan@chromium.org

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

Bug: 1037759
Change-Id: I64811d9a30b6ba98b395f6e4ea434958afa0b706
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2006248Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732654}

cc/trees/layer_tree_host.cc

@@ -1072,13 +1072,9 @@ void LayerTreeHost::RegisterViewportPropertyIds(
   DCHECK(IsUsingLayerLists());
   viewport_property_ids_ = ids;
   // Outer viewport properties exist only if inner viewport property exists.
-  // TODO(bokan): Temporarily make this a CHECK to debug crbug.com/1037759.
-  if (ids.inner_scroll == ScrollTree::kInvalidNodeId) {
-    CHECK_EQ(ids.outer_scroll, ScrollTree::kInvalidNodeId);
-    CHECK_EQ(ids.outer_clip, ClipTree::kInvalidNodeId);
-  } else {
-    CHECK_NE(ids.outer_scroll, ScrollTree::kInvalidNodeId);
-  }
+  DCHECK(ids.inner_scroll != ScrollTree::kInvalidNodeId ||
+         (ids.outer_scroll == ScrollTree::kInvalidNodeId &&
+          ids.outer_clip == ClipTree::kInvalidNodeId));
 }
 
 Layer* LayerTreeHost::InnerViewportScrollLayerForTesting() const {

cc/trees/layer_tree_impl.cc

@@ -259,13 +259,9 @@ void LayerTreeImpl::UpdateScrollbarGeometries() {
     if (is_viewport_scrollbar) {
       gfx::SizeF viewport_bounds(bounds_size);
       if (scroll_node->scrolls_inner_viewport) {
-        // TODO(bokan): Temporarily make these CHECKs to debug
-        // crbug.com/1037759.
-        CHECK_EQ(scroll_node, InnerViewportScrollNode());
+        DCHECK_EQ(scroll_node, InnerViewportScrollNode());
         auto* outer_scroll_node = OuterViewportScrollNode();
-        CHECK_NE(viewport_property_ids_.outer_scroll,
-                 ScrollTree::kInvalidNodeId);
-        CHECK(outer_scroll_node);
+        DCHECK(outer_scroll_node);
 
         // Add offset and bounds contribution of outer viewport.
         current_offset +=