Moved ExtensionMessage* into extensions 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 # running overnight and removing outdated bugs/suppressions.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 1949 matching lines @@
    Memcheck:Unaddressable
    ...
    fun:_ZN7WebCore13TextRunWalker13nextScriptRunEv
    fun:_ZN7WebCore13TextRunWalker14widthOfFullRunEv
 }
 {
    bug_51679
    Memcheck:Leak
    fun:_Znw*
    ...
-   fun:_ZN23ExtensionMessageService16AddEventListenerERKSsi
+   fun:_ZN23MessageService16AddEventListenerERKSsi
    fun:_ZN24BrowserRenderProcessHost22OnExtensionAddListenerERKSs
 }
 {
    bug_52831
    Memcheck:Leak
    fun:_Znw*
    ...
    fun:*InotifyReaderTask3RunEv
    ...
    fun:_ZN11MessageLoop11RunInternalEv
@@ skipping 3752 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
 }