Move the remaning files in content\common to the content namespace.

content/browser/renderer_host/render_sandbox_host_linux.h

Index: content/browser/renderer_host/render_sandbox_host_linux.h
===================================================================
--- content/browser/renderer_host/render_sandbox_host_linux.h	(revision 163632)
+++ content/browser/renderer_host/render_sandbox_host_linux.h	(working copy)
@@ -14,6 +14,8 @@
 
 template <typename T> struct DefaultSingletonTraits;
 
+namespace content {
+
 // This is a singleton object which handles sandbox requests from the
 // renderers.
 class CONTENT_EXPORT RenderSandboxHostLinux {
@@ -49,4 +51,6 @@
   DISALLOW_COPY_AND_ASSIGN(RenderSandboxHostLinux);
 };
 
+}  // namespace content
+
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_