Fix invalid selection produced when dragging mouse outside the SVG text element

third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp

Index: third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp b/third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp
index fbe5909f7a0917a37e843ac9a56c9a385ae59861..be5def8bbf1ac29a879dfbea665bed018c3d47ee 100644
--- a/third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp
@@ -28,6 +28,7 @@
 #include "core/layout/LayoutAnalyzer.h"
 #include "core/layout/LayoutPart.h"
 #include "core/layout/LayoutView.h"
+#include "core/layout/svg/LayoutSVGText.h"
 #include "core/layout/svg/SVGLayoutSupport.h"
 #include "core/layout/svg/SVGResourcesCache.h"
 #include "core/paint/PaintLayer.h"
@@ -281,6 +282,41 @@ void LayoutSVGRoot::willBeRemovedFromTree()
     LayoutReplaced::willBeRemovedFromTree();
 }
 
+PositionWithAffinity LayoutSVGRoot::positionForPoint(const LayoutPoint& point)
+{
+    FloatPoint absolutePoint = FloatPoint(point);
+    absolutePoint = m_localToBorderBoxTransform.inverse().mapPoint(absolutePoint);
+    LayoutObject* closestDescendant = SVGLayoutSupport::findSelectedLayoutSVGText(this, absolutePoint);
+
+    if (!closestDescendant)
+        return LayoutReplaced::positionForPoint(point);
+
+    LayoutObject* layoutObject = closestDescendant;
+    AffineTransform transform;
+    while (layoutObject) {

[fs, 2016/01/18 12:44:11]

The computation done by this loop does not look correct (the transform of
closestDescendant isn't included.)

+        layoutObject = layoutObject->parent();
+        if (layoutObject->isSVGRoot())
+            break;
+        transform = layoutObject->localToParentTransform() * transform;
+    }
+
+    AffineTransform closestDescendantTransform;
+    if (toLayoutSVGText(closestDescendant)->location().x())

[fs, 2016/01/18 12:44:11]

I don't see why this is needed.

[hyunjunekim2, 2016/01/18 13:32:48]

It needs codes. Because the transform is not applied to location of
LayoutSVGText.
So if no this codes, should disturb selection.

[fs, 2016/01/18 13:56:23]

Ah, this is compensating for the reverse thing in
LayoutSVGInlineText::positionForPoint... You could write this as
AffineTransform::translation(...) or transform.translate(...).

+        closestDescendantTransform.setE(toLayoutSVGText(closestDescendant)->location().x());
+    if (toLayoutSVGText(closestDescendant)->location().y())
+        closestDescendantTransform.setF(toLayoutSVGText(closestDescendant)->location().y());
+
+    transform = transform * closestDescendantTransform;
+
+    absolutePoint = transform.inverse().mapPoint(absolutePoint);
+    if (absolutePoint.x() < 0)

[fs, 2016/01/18 12:44:11]

Suggest to push this down into the callee chain.

+        absolutePoint.setX(0);
+    if (absolutePoint.y() < 0)
+        absolutePoint.setY(0);
+
+    return closestDescendant->positionForPoint(LayoutPoint(absolutePoint.x(), absolutePoint.y()));

[fs, 2016/01/18 12:44:11]

LayoutPoint(absolutePoint) should work just fine.

+}
+
 // LayoutBox methods will expect coordinates w/o any transforms in coordinates
 // relative to our borderBox origin.  This method gives us exactly that.
 void LayoutSVGRoot::buildLocalToBorderBoxTransform()