Expose fractional TouchEvent coordinates

Source/platform/geometry/FloatSize.h

Index: Source/platform/geometry/FloatSize.h
diff --git a/Source/platform/geometry/FloatSize.h b/Source/platform/geometry/FloatSize.h
index fc14bfdac89f7714bb2114149e3825b3d3722246..da6fc8d1c450bb55b48b86de4b1c52632ae8b950 100644
--- a/Source/platform/geometry/FloatSize.h
+++ b/Source/platform/geometry/FloatSize.h
@@ -102,6 +102,16 @@ public:
         return FloatSize(m_height, m_width);
     }
 
+    FloatSize scaledBy(float scale) const
+    {
+        return scaledBy(scale, scale);
+    }
+
+    FloatSize scaledBy(float scaleX, float scaleY) const
+    {
+        return FloatSize(m_width * scaleX, m_height * scaleY);
+    }
+
 #if OS(MACOSX)
     explicit FloatSize(const CGSize&); // don't do this implicitly since it's lossy
     operator CGSize() const;