Avoid "using namespace blink" in global scope

third_party/WebKit/Source/core/editing/WebSubstringUtil.mm

Index: third_party/WebKit/Source/core/editing/WebSubstringUtil.mm
diff --git a/third_party/WebKit/Source/core/editing/WebSubstringUtil.mm b/third_party/WebKit/Source/core/editing/WebSubstringUtil.mm
index ca0473fbe4eeadc7d971b6f3514b6152acc75909..752ed80813f50260bc9ce50a182fd54a4351d03c 100644
--- a/third_party/WebKit/Source/core/editing/WebSubstringUtil.mm
+++ b/third_party/WebKit/Source/core/editing/WebSubstringUtil.mm
@@ -58,11 +58,12 @@
 #include "public/web/WebHitTestResult.h"
 #include "public/web/WebLocalFrame.h"
 
-using namespace blink;
+namespace blink {
+
+namespace {
 
-static NSAttributedString* attributedSubstringFromRange(
-    const EphemeralRange& range,
-    float fontScale) {
+NSAttributedString* attributedSubstringFromRange(const EphemeralRange& range,
+                                                 float fontScale) {
   NSMutableAttributedString* string = [[NSMutableAttributedString alloc] init];
   NSMutableDictionary* attrs = [NSMutableDictionary dictionary];
   size_t length = range.EndPosition().ComputeOffsetInContainerNode() -
@@ -149,7 +150,7 @@ WebPoint getBaselinePoint(LocalFrameView* frameView,
   return stringPoint;
 }
 
-namespace blink {
+}  // namespace
 
 NSAttributedString* WebSubstringUtil::AttributedWordAtPoint(
     WebFrameWidget* frame_widget,