Valgrind: Update a suppression with the content namespace.

tools/valgrind/memcheck/suppressions.txt

 # There are four kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 3673 matching lines @@
    fun:g_slice_alloc
    fun:g_slice_alloc0
    fun:g_type_create_instance
    fun:g_object_constructor
    fun:g_object_newv
    fun:g_object_new
    fun:_gdk_window_impl_new
    fun:gdk_window_ensure_native
    fun:gdk_x11_drawable_get_xid
    fun:_ZN20GtkNativeViewManager14GetIdForWidgetEP10_GtkWidget
-   fun:_ZNK23RenderWidgetHostViewGtk15GetNativeViewIdEv
+   fun:_ZNK7content23RenderWidgetHostViewGtk15GetNativeViewIdEv
 }
 {
    bug_96402
    Memcheck:Leak
    fun:malloc
    fun:g_malloc
    fun:g_slice_alloc
    fun:g_slice_alloc0
    fun:g_type_create_instance
    fun:g_object_constructor
@@ skipping 2118 matching lines @@
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
 }
 {
    bug_todo_grep
    Memcheck:Leak
    fun:malloc
    obj:/bin/grep
    obj:/bin/grep
 }