Revert of Removing "using" declarations that import names in the C++ Standard library.

Source/core/editing/Editor.cpp

Index: Source/core/editing/Editor.cpp
diff --git a/Source/core/editing/Editor.cpp b/Source/core/editing/Editor.cpp
index d834513ea794ae905bafd1b1c9ee517659f80e66..c83d48d5e4fbd02617bd21b9970f1281ce8f04ee 100644
--- a/Source/core/editing/Editor.cpp
+++ b/Source/core/editing/Editor.cpp
@@ -88,6 +88,7 @@
 
 namespace WebCore {
 
+using namespace std;
 using namespace HTMLNames;
 using namespace WTF;
 using namespace Unicode;
@@ -1129,10 +1130,10 @@
 
     if (startCaretRect.y() == endCaretRect.y()) {
         // start and end are on the same line
-        return IntRect(std::min(startCaretRect.x(), endCaretRect.x()),
+        return IntRect(min(startCaretRect.x(), endCaretRect.x()),
             startCaretRect.y(),
-            std::abs(endCaretRect.x() - startCaretRect.x()),
-            std::max(startCaretRect.height(), endCaretRect.height()));
+            abs(endCaretRect.x() - startCaretRect.x()),
+            max(startCaretRect.height(), endCaretRect.height()));
     }
 
     // start and end aren't on the same line, so go from start to the end of its line