cc : Remove invalid DCHECK from draw_property_utils.cc

The DCHECK is invalid because we can have a render surface between the
target of scroll parent and scroll child.

BUG=663499
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2537053002
Cr-Commit-Position: refs/heads/master@{#435008}

cc/trees/draw_property_utils.cc

@@ -1229,10 +1229,15 @@ static void SetSurfaceClipRect(const ClipNode* parent_clip_node,
     return;
   }
 
-  DCHECK_LT(parent_clip_node->target_transform_id,
-            transform_tree.TargetId(transform_node->id));
-  render_surface->SetClipRect(gfx::ToEnclosingRect(MathUtil::ProjectClippedRect(
-      clip_parent_target_to_target, parent_clip_node->clip_in_target_space)));
+  if (parent_clip_node->target_transform_id <
+      transform_tree.TargetId(transform_node->id)) {
+    render_surface->SetClipRect(gfx::ToEnclosingRect(
+        MathUtil::ProjectClippedRect(clip_parent_target_to_target,
+                                     parent_clip_node->clip_in_target_space)));
+  } else {
+    render_surface->SetClipRect(gfx::ToEnclosingRect(MathUtil::MapClippedRect(
+        clip_parent_target_to_target, parent_clip_node->clip_in_target_space)));
+  }
 }
 
 template <typename LayerType>

cc/trees/layer_tree_host_common_unittest.cc

@@ -6302,6 +6302,50 @@ TEST_F(LayerTreeHostCommonTest, ScrollChildAndScrollParentDifferentTargets) {
   EXPECT_TRANSFORMATION_MATRIX_EQ(scroll_child->DrawTransform(), scale);
 }
 
+TEST_F(LayerTreeHostCommonTest, TargetBetweenScrollChildandScrollParentTarget) {
+  LayerImpl* root = root_layer_for_testing();
+  LayerImpl* scroll_child_target = AddChildToRoot<LayerImpl>();
+  LayerImpl* scroll_child = AddChild<LayerImpl>(scroll_child_target);
+  LayerImpl* child_of_scroll_child = AddChild<LayerImpl>(scroll_child);
+  LayerImpl* intervening_target = AddChild<LayerImpl>(scroll_child_target);
+  LayerImpl* clip = AddChild<LayerImpl>(intervening_target);
+  LayerImpl* scroll_parent_target = AddChild<LayerImpl>(clip);
+  LayerImpl* scroll_parent = AddChild<LayerImpl>(scroll_parent_target);
+
+  scroll_parent->SetDrawsContent(true);
+  child_of_scroll_child->SetDrawsContent(true);
+
+  scroll_child->test_properties()->scroll_parent = scroll_parent;
+  scroll_parent->test_properties()->scroll_children =
+      base::MakeUnique<std::set<LayerImpl*>>();
+  scroll_parent->test_properties()->scroll_children->insert(scroll_child);
+
+  root->SetBounds(gfx::Size(50, 50));
+  scroll_child_target->SetBounds(gfx::Size(50, 50));
+  scroll_child_target->SetMasksToBounds(true);
+  scroll_child_target->test_properties()->force_render_surface = true;
+  scroll_child->SetBounds(gfx::Size(50, 50));
+  child_of_scroll_child->SetBounds(gfx::Size(50, 50));
+  child_of_scroll_child->test_properties()->force_render_surface = true;
+  intervening_target->SetBounds(gfx::Size(50, 50));
+  intervening_target->test_properties()->force_render_surface = true;
+  clip->SetBounds(gfx::Size(50, 50));
+  clip->SetMasksToBounds(true);
+  scroll_parent_target->SetBounds(gfx::Size(50, 50));
+  scroll_parent_target->SetMasksToBounds(true);
+  scroll_parent_target->test_properties()->force_render_surface = true;
+  scroll_parent->SetBounds(gfx::Size(50, 50));
+
+  ExecuteCalculateDrawProperties(root);
+  PropertyTrees* property_trees = root->layer_tree_impl()->property_trees();
+  ClipNode* clip_node =
+      property_trees->clip_tree.Node(child_of_scroll_child->clip_tree_index());
+  ClipNode* parent_clip_node = property_trees->clip_tree.parent(clip_node);
+  DCHECK_GT(parent_clip_node->target_transform_id,
+            property_trees->transform_tree.TargetId(
+                child_of_scroll_child->transform_tree_index()));
+}
+
 TEST_F(LayerTreeHostCommonTest, SingularTransformSubtreesDoNotDraw) {
   LayerImpl* root = root_layer_for_testing();
   LayerImpl* parent = AddChildToRoot<LayerImpl>();