mac: Delete more 10.5-only code

chrome/browser/gpu_util.cc

Index: chrome/browser/gpu_util.cc
diff --git a/chrome/browser/gpu_util.cc b/chrome/browser/gpu_util.cc
index 2af41916a7d4bd6b3cecbce1c0703c7d09d32d58..730aa722c0bab7b44508d0a2e09be5ca74dc6a35 100644
--- a/chrome/browser/gpu_util.cc
+++ b/chrome/browser/gpu_util.cc
@@ -25,8 +25,6 @@
 
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
-#elif defined(OS_MACOSX)
-#include "base/mac/mac_util.h"
 #endif
 
 using content::GpuDataManager;
@@ -183,10 +181,6 @@ void InitializeCompositingFieldTrial() {
   // Don't run the trial on Windows XP.
   if (base::win::GetVersion() < base::win::VERSION_VISTA)
     return;
-#elif defined(OS_MACOSX)
-  // Accelerated compositing is only implemented on Mac OSX 10.6 or later.
-  if (base::mac::IsOSLeopardOrEarlier())
-    return;
 #endif
 
   // The performance of accelerated compositing is too low with software