Cleanup namespace usage in Source/core/{dom/* & fileapi/*}

Source/core/dom/Microtask.h

Index: Source/core/dom/Microtask.h
diff --git a/Source/core/dom/Microtask.h b/Source/core/dom/Microtask.h
index 6e54b404f0482ecbf0721d97c40d0464f2ae70e0..a0fbdcb1e4b2bfa6d7e07bf9a780938b6153ed35 100644
--- a/Source/core/dom/Microtask.h
+++ b/Source/core/dom/Microtask.h
@@ -40,13 +40,13 @@ namespace blink {
 class Microtask {
 public:
     static void performCheckpoint();
-    static void enqueueMicrotask(PassOwnPtr<blink::WebThread::Task>);
+    static void enqueueMicrotask(PassOwnPtr<WebThread::Task>);
     static void enqueueMicrotask(const Closure&);
 
 private:
     explicit Microtask();
 };
 
-}
+} // namespace blink
 
 #endif // Microtask_h