wm: Update namespace and header define guards.

src/platform/window_manager/shadow.cc

Index: src/platform/window_manager/shadow.cc
diff --git a/src/platform/window_manager/shadow.cc b/src/platform/window_manager/shadow.cc
index c678e1d28343b6d009dee85defceb249646d111b..22130af89adf4fedadbd00bfba4164b18aec7e3f 100644
--- a/src/platform/window_manager/shadow.cc
+++ b/src/platform/window_manager/shadow.cc
@@ -12,7 +12,7 @@
 DEFINE_string(shadow_image_dir, "../assets/images",
               "Path to directory containing shadow images");
 
-namespace chromeos {
+namespace window_manager {
 
 // Static members.
 ClutterInterface::Actor* Shadow::top_texture_    = NULL;
@@ -156,4 +156,4 @@ ClutterInterface::Actor* Shadow::InitTexture(const std::string& filename) {
   return actor;
 }
 
-}  // namespace chromeos
+}  // namespace window_manager