Move property tree debugging code to platform/graphics/paint/ (try #2)

third_party/WebKit/Source/platform/graphics/paint/PropertyTreeState.h

Index: third_party/WebKit/Source/platform/graphics/paint/PropertyTreeState.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/PropertyTreeState.h b/third_party/WebKit/Source/platform/graphics/paint/PropertyTreeState.h
index 19555592996153b78883df9520f1af9cc9f6b1c2..22d308f37e2e372cd39186d63c03a70d9a120831 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PropertyTreeState.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/PropertyTreeState.h
@@ -11,6 +11,7 @@
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "wtf/HashFunctions.h"
 #include "wtf/HashTraits.h"
+#include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
@@ -112,6 +113,11 @@ class PLATFORM_EXPORT PropertyTreeState {
   // DCHECK(iterator.next()->innermostNode() == None);
   InnermostNode innermostNode() const;
 
+#if DCHECK_IS_ON()
+  // Dumps the tree from this state up to the root as a string.
+  String toTreeString() const;
+#endif
+
  private:
   RefPtr<const TransformPaintPropertyNode> m_transform;
   RefPtr<const ClipPaintPropertyNode> m_clip;
@@ -139,6 +145,51 @@ class PLATFORM_EXPORT PropertyTreeStateIterator {
   PropertyTreeState m_properties;
 };
 
+#if DCHECK_IS_ON()
+
+template <typename PropertyTreeNode>
+class PropertyTreeStatePrinter {
+ public:
+  String pathAsString(const PropertyTreeNode* lastNode) {
+    const PropertyTreeNode* node = lastNode;
+    while (!node->isRoot()) {
+      addPropertyNode(node, "");
+      node = node->parent();
+    }
+    addPropertyNode(node, "root");
+
+    StringBuilder stringBuilder;
+    addAllPropertyNodes(stringBuilder, node);
+    return stringBuilder.toString();
+  }
+
+  void addPropertyNode(const PropertyTreeNode* node, String debugInfo) {
+    m_nodeToDebugString.set(node, debugInfo);
+  }
+
+  void addAllPropertyNodes(StringBuilder& stringBuilder,
+                           const PropertyTreeNode* node,
+                           unsigned indent = 0) {
+    DCHECK(node);
+    for (unsigned i = 0; i < indent; i++)
+      stringBuilder.append(' ');
+    if (m_nodeToDebugString.contains(node))
+      stringBuilder.append(m_nodeToDebugString.get(node));
+    stringBuilder.append(String::format(" %p ", node));
+    stringBuilder.append(node->toString());
+    stringBuilder.append("\n");
+
+    for (const auto* childNode : m_nodeToDebugString.keys()) {
+      if (childNode->parent() == node)
+        addAllPropertyNodes(stringBuilder, childNode, indent + 2);
+    }
+  }
+
+  HashMap<const PropertyTreeNode*, String> m_nodeToDebugString;
+};
+
+#endif
+
 }  // namespace blink
 
 #endif  // PropertyTreeState_h