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

Source/core/page/TouchDisambiguation.cpp

Index: Source/core/page/TouchDisambiguation.cpp
diff --git a/Source/core/page/TouchDisambiguation.cpp b/Source/core/page/TouchDisambiguation.cpp
index fe825b8bf579e92cba96d758810205794e82ee9e..c74cf5599538ea28932f87404af4b3706f261557 100644
--- a/Source/core/page/TouchDisambiguation.cpp
+++ b/Source/core/page/TouchDisambiguation.cpp
@@ -45,6 +45,8 @@
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderBlock.h"
 
+using namespace std;
+
 namespace WebCore {
 
 static IntRect boundingBoxForEventNodes(Node* eventNode)
@@ -75,8 +77,8 @@
     float score = 1;
 
     IntSize distance = boundingBox.differenceToPoint(touchPoint);
-    score *= std::max((padding - std::abs(distance.width())) * reciprocalPadding, 0.f);
-    score *= std::max((padding - std::abs(distance.height())) * reciprocalPadding, 0.f);
+    score *= max((padding - abs(distance.width())) * reciprocalPadding, 0.f);
+    score *= max((padding - abs(distance.height())) * reciprocalPadding, 0.f);
 
     return score;
 }
@@ -90,7 +92,7 @@
 {
     goodTargets.clear();
 
-    int touchPointPadding = ceil(std::max(touchBox.width(), touchBox.height()) * 0.5);
+    int touchPointPadding = ceil(max(touchBox.width(), touchBox.height()) * 0.5);
 
     IntPoint touchPoint = touchBox.center();
     IntPoint contentsPoint = mainFrame->view()->windowToContents(touchPoint);
@@ -130,7 +132,7 @@
                 TouchTargetData& targetData = touchTargets.add(node, TouchTargetData()).storedValue->value;
                 targetData.windowBoundingBox = boundingBoxForEventNodes(node);
                 targetData.score = scoreTouchTarget(touchPoint, touchPointPadding, targetData.windowBoundingBox);
-                bestScore = std::max(bestScore, targetData.score);
+                bestScore = max(bestScore, targetData.score);
                 break;
             }
         }