Revert parts of http://codereview.chromium.org/2808079 as requested by thestig.

tools/valgrind/memcheck/suppressions_mac.txt

 # There are three kinds of suppressions in this file:
 # 1. Third party stuff we have no control over.
 #
 # 2. Intentional unit test errors, 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.
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 203 matching lines @@
    fun:_Znw*
    fun:_ZN11sandboxtest8internal19RegisterSandboxTestIN12_GLOBAL__N_*
    fun:_Z41__static_initialization_and_destruction_0ii
    fun:_GLOBAL__I__ZNSt3tr112_GLOBAL__N_16ignoreE
    fun:_ZN16ImageLoaderMachO18doModInitFunctionsERKN11ImageLoader11LinkContextE
    fun:_ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextEj
    fun:_ZN11ImageLoader15runInitializersERKNS_11LinkContextE
    fun:_ZN4dyld24initializeMainExecutableEv
 }
 {
+   # With our tweaks to get Chromium to link on Mac 10.5, we sometimes get      
+   # this suppression instead.  
+   Mac_Sandbox_Intentional_Leak3        
+   Memcheck:Leak        
+   fun:_Znw*    
+   fun:_Z41__static_initialization_and_destruction_0ii  
+   fun:_ZN16ImageLoaderMachO18doModInitFunctionsERKN11ImageLoader11LinkContextE 
+   fun:_ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextEj   
+   fun:_ZN11ImageLoader15runInitializersERKNS_11LinkContextE    
+   fun:_ZN4dyld24initializeMainExecutableEv     
+}
+{
    # jrg thinks this is probably a bug in Cocoa but is harmless.  We
    # can hit it by using --homepage=about:blank, which triggers a
    # location bar focus earlier than normal (earlier than when a
    # window is shown).  To "work around" the problem for valgrind, we
    # could call for example call [NSWindow setInitialFirstResponder:]
    # instead of [NSWindow makeFirstResponder:] if the window isn't
    # visible.  However, these contortions are ugly.  since the
    # needsDisplay region gets reset when the window is shown, it
    # really doesn't matter what we do with it before then.
    Memcheck:Cond
@@ skipping 1309 matching lines @@
    bug_50638
    Memcheck:Cond
    fun:gleUpdateViewScissorData
    ...
    fun:cgl_set_surface
    fun:ogl_attach_surface
    fun:ogl_render_fade_transition
    fun:ogl_render_layer_
    fun:ogl_render_layers
 }