Change cc::ElementId to be a uint64_t

third_party/WebKit/Source/platform/graphics/CompositorElementId.cpp

Index: third_party/WebKit/Source/platform/graphics/CompositorElementId.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/CompositorElementId.cpp b/third_party/WebKit/Source/platform/graphics/CompositorElementId.cpp
index eeb495fbacd4780e0671a07ae53022b945c3aa39..eec2d1131b72df13f5a32912641ffd4d0026fd6b 100644
--- a/third_party/WebKit/Source/platform/graphics/CompositorElementId.cpp
+++ b/third_party/WebKit/Source/platform/graphics/CompositorElementId.cpp
@@ -7,9 +7,27 @@
 namespace blink {
 
 CompositorElementId CreateCompositorElementId(
-    int dom_node_id,
+    DOMNodeId dom_node_id,
     CompositorSubElementId sub_element_id) {
-  return CompositorElementId(dom_node_id, static_cast<int>(sub_element_id));
+  DCHECK(dom_node_id > 0 &&
+         dom_node_id < std::numeric_limits<DOMNodeId>::max() /
+                           static_cast<unsigned>(
+                               CompositorSubElementId::kNumSubElementTypes));
+  cc::ElementIdType id =
+      dom_node_id << 2;  // Shift to make room for sub_element_id enum bits.
+  id += static_cast<uint64_t>(sub_element_id);
+  return CompositorElementId(id);
+}
+
+DOMNodeId DomNodeIdFromCompositorElementId(CompositorElementId element_id) {
+  return element_id.id_ >> 2;
+}
+
+CompositorSubElementId SubElementIdFromCompositorElementId(
+    CompositorElementId element_id) {
+  return static_cast<CompositorSubElementId>(
+      element_id.id_ %
+      static_cast<unsigned>(CompositorSubElementId::kNumSubElementTypes));
 }
 
 }  // namespace blink