Implement FloatRect::squaredDistanceTo function

third_party/WebKit/Source/platform/geometry/FloatRect.cpp

Index: third_party/WebKit/Source/platform/geometry/FloatRect.cpp
diff --git a/third_party/WebKit/Source/platform/geometry/FloatRect.cpp b/third_party/WebKit/Source/platform/geometry/FloatRect.cpp
index 13c4b815ff075a05fdba414b6d9e395ed78e6e63..6ff8f28e593989563fd9df1ad723a208809f5097 100644
--- a/third_party/WebKit/Source/platform/geometry/FloatRect.cpp
+++ b/third_party/WebKit/Source/platform/geometry/FloatRect.cpp
@@ -171,6 +171,35 @@ void FloatRect::scale(float sx, float sy)
     m_size.setHeight(height() * sy);
 }
 
+float FloatRect::distanceTo(const FloatPoint& point)
+{
+    float distance = 0.f;
+    if (point.x() < this->x()) {

[fs, 2016/01/13 10:22:03]

I don't see the need for explicit this - here and elsewhere.

+        if (point.y() < this->y())
+            distance = (point - FloatPoint(this->x(), this->y())).diagonalLengthSquared();

[fs, 2016/01/13 10:22:03]

FloatRect has minXMinYCorner (etc.) which would make these slightly easier to
read IMHO.

+        else if (point.y() > this->maxY())
+            distance = (point - FloatPoint(this->x(), this->maxY())).diagonalLengthSquared();

[fs, 2016/01/13 10:22:03]

The 'corner' areas compute the squared distance while the other areas compute
"proper" distances. Squared distances often makes sense, but regardless all
cases should use the same convention. Calling the method just "distanceTo" I'd
expect the Euclidian norm though (else "squaredDistanceTo" if a squared distance
was returned.)

+        else
+            distance = this->x() - point.x();
+    } else if (point.x() > this->maxX()) {
+        if (point.y() < this->y())
+            distance = (point - FloatPoint(this->maxX(), this->y())).diagonalLengthSquared();
+        else if (point.y() > this->maxY())
+            distance = (point - FloatPoint(this->maxX(), this->maxY())).diagonalLengthSquared();
+        else
+            distance = point.x() - this->maxX();
+    } else {
+        if (point.y() < this->y())
+            distance = this->y() - point.y();
+        else if (point.y() > this->maxY())
+            distance = point.y() - this->maxY();
+        else
+            distance = 0.f;
+    }
+
+    return distance;
+}
+
 FloatRect unionRect(const Vector<FloatRect>& rects)
 {
     FloatRect result;