Rename WebCore namespace to blink in Platform

Source/platform/scroll/ScrollbarThemeMacCommon.mm

Index: Source/platform/scroll/ScrollbarThemeMacCommon.mm
diff --git a/Source/platform/scroll/ScrollbarThemeMacCommon.mm b/Source/platform/scroll/ScrollbarThemeMacCommon.mm
index d4096ae3ee1bcfefd1e181d36b9ed19a87d103c7..076e588187c1f236735e4830c35aa359dea4df2b 100644
--- a/Source/platform/scroll/ScrollbarThemeMacCommon.mm
+++ b/Source/platform/scroll/ScrollbarThemeMacCommon.mm
@@ -53,13 +53,13 @@
 // FIXME: There are repainting problems due to Aqua scroll bar buttons' visual overflow.
 
 using namespace std;
-using namespace WebCore;
+using namespace blink;
 
 @interface NSColor (WebNSColorDetails)
 + (NSImage *)_linenPatternImage;
 @end
 
-namespace WebCore {
+namespace blink {
 
 typedef HashSet<ScrollbarThemeClient*> ScrollbarSet;
 
@@ -361,4 +361,4 @@ bool ScrollbarThemeMacCommon::isOverlayAPIAvailable()
     return apiAvailable;
 }
 
-} // namespace WebCore
+} // namespace blink