DevTools: Force a layout in DOM.getBoundingBox

If the style of a node was changed right before a call to
DOM.getBoundingBox, it might return stale metrics.

Change-Id: I046ecd214c964935f5912ed6f570c9cc4552ad29
Reviewed-on: https://chromium-review.googlesource.com/963302Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Andrey Lushnikov <lushnikov@chromium.org>
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543202}

third_party/WebKit/Source/core/inspector/InspectorHighlight.cpp

@@ -453,6 +453,7 @@ std::unique_ptr<protocol::DictionaryValue> InspectorHighlight::AsProtocolValue()
 bool InspectorHighlight::GetBoxModel(
     Node* node,
     std::unique_ptr<protocol::DOM::BoxModel>* model) {
+  node->GetDocument().EnsurePaintLocationDataValidForNode(node);
   LayoutObject* layout_object = node->GetLayoutObject();
   LocalFrameView* view = node->GetDocument().View();
   if (!layout_object || !view)