Rename VulkanViewer to Viewer, take 2.

tools/viewer/Window.cpp

Index: tools/viewer/Window.cpp
diff --git a/tools/vulkan/Window.cpp b/tools/viewer/Window.cpp
similarity index 97%
rename from tools/vulkan/Window.cpp
rename to tools/viewer/Window.cpp
index 9042a0cb699df29969a3d5aa6bd3f2854fd464f1..6a83a3ba815d8ccb60b43eda9bb7be3de64f445d 100644
--- a/tools/vulkan/Window.cpp
+++ b/tools/viewer/Window.cpp
@@ -11,6 +11,8 @@
 #include "SkCanvas.h"
 #include "VulkanTestContext.h"
 
+namespace sk_app {
+
 static bool default_char_func(SkUnichar c, uint32_t modifiers, void* userData) {
     return false;
 }
@@ -72,3 +74,5 @@ void Window::onResize(uint32_t w, uint32_t h) {
     fHeight = h;
     fTestContext->resize(w, h);
 }
+
+}   // namespace sk_app