Add a DOM.getLayoutTreeNodes devtools command

third_party/WebKit/Source/core/inspector/browser_protocol.json

Index: third_party/WebKit/Source/core/inspector/browser_protocol.json
diff --git a/third_party/WebKit/Source/core/inspector/browser_protocol.json b/third_party/WebKit/Source/core/inspector/browser_protocol.json
index ea4a945b5c899ba33e8a7f1e530119559cfe4437..b22272034f2a382b6d99ff31c3a5ad25f9c29612 100644
--- a/third_party/WebKit/Source/core/inspector/browser_protocol.json
+++ b/third_party/WebKit/Source/core/inspector/browser_protocol.json
@@ -2061,6 +2061,28 @@
                 "description": "DOM interaction is implemented in terms of mirror objects that represent the actual DOM nodes. DOMNode is a base node mirror type."
             },
             {
+                "id": "InlineTextBox",
+                "type": "object",
+                "properties": [
+                    { "name": "boundingBox", "$ref": "Rect", "description": "The absolute position bounding box." },
+                    { "name": "text", "type": "string", "description": "Post layout inline text snippet." }
+                ],
+                "description": "Details of post layout rendered text positions.",
+                "experimental": true
+            },
+            {
+                "id": "LayoutTreeNode",
+                "type": "object",
+                "properties": [
+                    { "name": "backendNodeId", "$ref": "BackendNodeId", "description": "The BackendNodeId of the related DOM node." },
+                    { "name": "boundingBox", "$ref": "Rect", "description": "The absolute position bounding box." },
+                    { "name": "layoutText", "type": "string", "optional": true, "description": "Contents of the LayoutText if any" },
+                    { "name": "inlineTextNodes", "type": "array", "optional": true, "items": { "$ref": "InlineTextBox" }, "description": "The post layout inline text nodes, if any." }
+                ],
+                "description": "Details of an element in the DOM tree with a LayoutObject.",
+                "experimental": true
+            },
+            {
                 "id": "RGBA",
                 "type": "object",
                 "properties": [
@@ -2166,6 +2188,14 @@
                 "description": "Returns the root DOM node to the caller."
             },
             {
+                "name": "getLayoutTreeNodes",
+                "returns": [
+                    { "name": "layoutTreeNodes", "type": "array", "items": { "$ref": "LayoutTreeNode" } }
+                ],
+                "description": "Returns the document's LayoutTreeNodes to the caller.",
+                "experimental": true
+            },
+            {
                 "name": "collectClassNamesFromSubtree",
                 "parameters": [
                     { "name": "nodeId", "$ref": "NodeId", "description": "Id of the node to collect class names." }