Move libplatform files into v8::platform namespace

src/libplatform/default-platform.h

Index: src/libplatform/default-platform.h
diff --git a/src/libplatform/default-platform.h b/src/libplatform/default-platform.h
index 14e002b882b79446d9ddad295534d0a124209ff1..c5f6fae3abaf79a97d405f5837774af1fd408b7f 100644
--- a/src/libplatform/default-platform.h
+++ b/src/libplatform/default-platform.h
@@ -13,7 +13,7 @@
 #include "src/libplatform/task-queue.h"
 
 namespace v8 {
-namespace internal {
+namespace platform {
 
 class TaskQueue;
 class Thread;
@@ -47,7 +47,7 @@ class DefaultPlatform : public Platform {
 };
 
 
-} }  // namespace v8::internal
+} }  // namespace v8::platform
 
 
 #endif  // V8_LIBPLATFORM_DEFAULT_PLATFORM_H_