Rename VulkanViewer to Viewer, take 2.

tools/viewer/win/Window_win.cpp

Index: tools/viewer/win/Window_win.cpp
diff --git a/tools/vulkan/win/Window_win.cpp b/tools/viewer/win/Window_win.cpp
similarity index 99%
rename from tools/vulkan/win/Window_win.cpp
rename to tools/viewer/win/Window_win.cpp
index 58224d6d51817c2647655a2c651b2867f309a354..d5711b72452ebf7c1b0d1297862876f40b63a75e 100644
--- a/tools/vulkan/win/Window_win.cpp
+++ b/tools/viewer/win/Window_win.cpp
@@ -14,6 +14,8 @@
 #include "SkUtils.h"
 #include "VulkanTestContext_win.h"
 
+namespace sk_app {
+
 Window* Window::CreateNativeWindow(void* platformData) {
     HINSTANCE hInstance = (HINSTANCE)platformData;
 
@@ -279,3 +281,5 @@ bool Window_win::attach(BackEndType attachType, int msaaSampleCount) {
 void Window_win::inval() {
     InvalidateRect(fHWnd, nullptr, false);
 }
+
+}   // namespace sk_app