Update uses of UTF conversions in content/ to use the base:: namespace.

content/worker/worker_webkitplatformsupport_impl.cc

Index: content/worker/worker_webkitplatformsupport_impl.cc
diff --git a/content/worker/worker_webkitplatformsupport_impl.cc b/content/worker/worker_webkitplatformsupport_impl.cc
index 1d7b326587250a793798a6580d94db6e1bf34701..23fb80ea08dfbac831f95b7dbd6c431b3c4b114f 100644
--- a/content/worker/worker_webkitplatformsupport_impl.cc
+++ b/content/worker/worker_webkitplatformsupport_impl.cc
@@ -264,7 +264,7 @@ WebString WorkerWebKitPlatformSupportImpl::mimeTypeForExtension(
   std::string mime_type;
   thread_safe_sender_->Send(new MimeRegistryMsg_GetMimeTypeFromExtension(
       base::FilePath::FromUTF16Unsafe(file_extension).value(), &mime_type));
-  return ASCIIToUTF16(mime_type);
+  return base::ASCIIToUTF16(mime_type);
 }
 
 WebString WorkerWebKitPlatformSupportImpl::wellKnownMimeTypeForExtension(
@@ -272,7 +272,7 @@ WebString WorkerWebKitPlatformSupportImpl::wellKnownMimeTypeForExtension(
   std::string mime_type;
   net::GetWellKnownMimeTypeFromExtension(
       base::FilePath::FromUTF16Unsafe(file_extension).value(), &mime_type);
-  return ASCIIToUTF16(mime_type);
+  return base::ASCIIToUTF16(mime_type);
 }
 
 WebString WorkerWebKitPlatformSupportImpl::mimeTypeFromFile(
@@ -282,7 +282,7 @@ WebString WorkerWebKitPlatformSupportImpl::mimeTypeFromFile(
       new MimeRegistryMsg_GetMimeTypeFromFile(
           base::FilePath::FromUTF16Unsafe(file_path),
           &mime_type));
-  return ASCIIToUTF16(mime_type);
+  return base::ASCIIToUTF16(mime_type);
 }
 
 WebBlobRegistry* WorkerWebKitPlatformSupportImpl::blobRegistry() {