Add a DOM.getLayoutTreeNodes devtools command

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

Index: third_party/WebKit/Source/core/inspector/InspectorDOMAgent.cpp
diff --git a/third_party/WebKit/Source/core/inspector/InspectorDOMAgent.cpp b/third_party/WebKit/Source/core/inspector/InspectorDOMAgent.cpp
index 0ceb294c59525ae7a89873664d29373976394f87..0e84a8739a25a05b9db64f193acfbed5496abe4a 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorDOMAgent.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorDOMAgent.cpp
@@ -67,7 +67,9 @@
 #include "core/inspector/InspectorHistory.h"
 #include "core/inspector/V8InspectorString.h"
 #include "core/layout/HitTestResult.h"
+#include "core/layout/LayoutInline.h"
 #include "core/layout/api/LayoutViewItem.h"
+#include "core/layout/line/InlineTextBox.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
@@ -136,8 +138,36 @@ v8::Local<v8::Value> nodeV8Value(v8::Local<v8::Context> context, Node* node)
     return toV8(node, context->Global(), isolate);
 }
 
+std::unique_ptr<protocol::DOM::Rect> buildRectForFloatRect(const FloatRect& rect)
+{
+    return protocol::DOM::Rect::create()
+        .setX(rect.x())
+        .setY(rect.y())
+        .setWidth(rect.width())
+        .setHeight(rect.height())
+        .build();
+}
+
+FloatRect buildAbsoluteBoundingBox(LayoutObject* layoutObject)

[esprehn, 2016/09/28 04:02:49]

I think you want to use boundsInViewport() from the DOM instead? This function
is using the very low level stuff, and feels like duplication.

[alex clarke (OOO till 29th), 2016/09/28 17:15:20]

Done.

+{
+    if (layoutObject->isText()) {
+        FloatRect localRect(toLayoutText(layoutObject)->linesBoundingBox());
+        return layoutObject->localToAbsoluteQuad(localRect).boundingBox();
+    }
+    if (layoutObject->isLayoutInline()) {
+        FloatRect localRect(toLayoutInline(layoutObject)->linesBoundingBox());
+        return layoutObject->localToAbsoluteQuad(localRect).boundingBox();
+    }
+    if (layoutObject->isBox()) {
+        FloatRect localRect(toLayoutBox(layoutObject)->borderBoxRect());
+        return layoutObject->localToAbsoluteQuad(localRect).boundingBox();
+    }
+    return layoutObject->absoluteBoundingBoxRect();
+}
+
 } // namespace
 
+
 class InspectorRevalidateDOMTask final : public GarbageCollectedFinalized<InspectorRevalidateDOMTask> {
 public:
     explicit InspectorRevalidateDOMTask(InspectorDOMAgent*);
@@ -529,6 +559,67 @@ void InspectorDOMAgent::getDocument(ErrorString* errorString, std::unique_ptr<pr
     *root = buildObjectForNode(m_document.get(), 2, m_documentNodeToIdMap.get());
 }
 
+void InspectorDOMAgent::getLayoutTreeNodes(ErrorString* errorString, std::unique_ptr<protocol::Array<protocol::DOM::LayoutTreeNode>>* layoutTreeNodes)
+{
+    layoutTreeNodes->reset(new protocol::Array<protocol::DOM::LayoutTreeNode>);
+
+    std::vector<Node*> unvisited; // Neither WTF::Vector or HeapVector allow Node* :(

[esprehn, 2016/09/28 04:02:49]

HeapVector<Member<Node>>, you probably want a big inline capacity too to avoid
the malloc cost

[alex clarke (OOO till 29th), 2016/09/28 17:15:20]

Done.

+    unvisited.push_back(m_document.get());
+
+    while (!unvisited.empty()) {

[esprehn, 2016/09/28 04:02:49]

this is very strange to put everything into a vector, just iterate the document
with Traversal.

[alex clarke (OOO till 29th), 2016/09/28 17:15:20]

Done.

+        Node* node = unvisited.back();
+        unvisited.pop_back();
+
+        // Visit shadow dom nodes.
+        if (node->isElementNode()) {
+            const Element* element = toElement(node);
+            ElementShadow* elementShadow = element->shadow();
+            if (elementShadow)
+                unvisited.push_back(&elementShadow->youngestShadowRoot());
+        }
+
+        // Pierce iframe boundaries.
+        if (node->isFrameOwnerElement()) {
+            unvisited.push_back(toHTMLFrameOwnerElement(node)->contentDocument()->documentElement());
+        }
+
+        for (Node* child = innerFirstChild(node); child; child = innerNextSibling(child)) {
+            unvisited.push_back(child);
+        }
+
+        LayoutObject* layoutObject = node->layoutObject();
+        if (!layoutObject)
+            continue;
+
+        int backendNodeId = DOMNodeIds::idForNode(node);
+        std::unique_ptr<protocol::DOM::LayoutTreeNode> layoutTreeNode =
+            protocol::DOM::LayoutTreeNode::create()
+                .setBackendNodeId(backendNodeId)
+                .setBoundingBox(buildRectForFloatRect(buildAbsoluteBoundingBox(layoutObject)))
+                .build();
+
+        if (layoutObject->isText()) {
+            LayoutText* layoutText = toLayoutText(layoutObject);
+            layoutTreeNode->setLayoutText(layoutText->text());
+            if (layoutText->hasTextBoxes()) {
+                std::unique_ptr<protocol::Array<protocol::DOM::InlineTextBox>> inlineTextNodes(new protocol::Array<protocol::DOM::InlineTextBox>());
+                for (const InlineTextBox* itb = layoutText->firstTextBox(); itb; itb = itb->nextTextBox()) {

[esprehn, 2016/09/28 04:02:49]

box or textBox

[alex clarke (OOO till 29th), 2016/09/28 17:15:20]

Done.

+                    FloatRect localItbRect(itb->calculateBoundaries());
+                    FloatRect absoluteItbRect = layoutObject->localToAbsoluteQuad(localItbRect).boundingBox();

[esprehn, 2016/09/28 04:02:49]

what is Itb? Don't abbreciate in blink

[alex clarke (OOO till 29th), 2016/09/28 17:15:20]

Done.

+                    inlineTextNodes->addItem(
+                        protocol::DOM::InlineTextBox::create()
+                            .setText(layoutText->text().substring(itb->start(), itb->len()).utf8().data())

[esprehn, 2016/09/28 04:02:49]

this is allocating tons of strings and will be slow, you do 3 string copies in
here. Also accessing the low level API like start() and len() is unfortunate,
we're trying to get people to stop doing that. :)

[alex clarke (OOO till 29th), 2016/09/28 17:15:20]

We don't really need the substring, the offset and length suffice although the
user has to be cautious since the units are characters not bytes.

+                            .setBoundingBox(buildRectForFloatRect(absoluteItbRect))
+                            .build());
+                }
+                layoutTreeNode->setInlineTextNodes(std::move(inlineTextNodes));
+            }
+        }
+
+        (*layoutTreeNodes)->addItem(std::move(layoutTreeNode));
+    }
+}
+
 void InspectorDOMAgent::pushChildNodesToFrontend(int nodeId, int depth)
 {
     Node* node = nodeForId(nodeId);