Add a DOM.getLayoutTreeNodes devtools command

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

 {
     "version": { "major": "1", "minor": "2" },
     "domains": [{
         "domain": "Inspector",
         "experimental": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications.",
@@ skipping 2043 matching lines @@
                     { "name": "contentDocument", "$ref": "Node", "optional": true, "description": "Content document for frame owner elements." },
                     { "name": "shadowRoots", "type": "array", "optional": true, "items": { "$ref": "Node" }, "description": "Shadow root list for given element host.", "experimental": true },
                     { "name": "templateContent", "$ref": "Node", "optional": true, "description": "Content document fragment for template elements.", "experimental": true },
                     { "name": "pseudoElements", "type": "array", "items": { "$ref": "Node" }, "optional": true, "description": "Pseudo elements associated with this node.", "experimental": true },
                     { "name": "importedDocument", "$ref": "Node", "optional": true, "description": "Import document for the HTMLImport links." },
                     { "name": "distributedNodes", "type": "array", "items": { "$ref": "BackendNode" }, "optional": true, "description": "Distributed nodes for given insertion point.", "experimental": true }
                 ],
                 "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": [
                     { "name": "r", "type": "integer", "description": "The red component, in the [0-255] range." },
                     { "name": "g", "type": "integer", "description": "The green component, in the [0-255] range." },
                     { "name": "b", "type": "integer", "description": "The blue component, in the [0-255] range." },
                     { "name": "a", "type": "number", "optional": true, "description": "The alpha component, in the [0-1] range (default: 1)." }
                 ],
                 "description": "A structure holding an RGBA color."
             },
@@ skipping 85 matching lines @@
                 "description": "Disables DOM agent for the given page."
             },
             {
                 "name": "getDocument",
                 "returns": [
                     { "name": "root", "$ref": "Node", "description": "Resulting node." }
                 ],
                 "description": "Returns the root DOM node to the caller."
             },
             {
+                "name": "getLayoutTreeNodes",
+                "returns": [
+                    { "name": "layoutTreeNodes", "type": "array", "items": { "$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." }
                 ],
                 "returns": [
                     {"name": "classNames", "type": "array", "items": { "type": "string" }, "description": "Class name list." }
                 ],
                 "description": "Collects class names for the node with given id and all of it's child nodes.",
                 "experimental": true
             },
@@ skipping 2365 matching lines @@
                 "description": "Informs that port was successfully bound and got a specified connection id.",
                 "parameters": [
                     {"name": "port", "type": "integer", "description": "Port number that was successfully bound." },
                     {"name": "connectionId", "type": "string", "description": "Connection id to be used." }
                 ],
                 "handlers": ["browser"]
             }
         ]
     }]
 }