Remove extern keyword in definition

For consistency with other definition in the same file.
Extern declaration already did in chrome_constants.h

BUG=NONE
TEST=Compiles


Review URL: https://chromiumcodereview.appspot.com/11428142

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@170940 0039d316-1c4b-4281-b951-d872f2087c98

chrome/common/chrome_constants.cc

@@ -227,8 +227,8 @@ const bool kEnableTouchIcon = false;
 const float kMaxShareOfExtensionProcesses = 0.30f;
 
 #if defined(OS_LINUX)
-extern const int kLowestRendererOomScore = 300;
-extern const int kHighestRendererOomScore = 1000;
+const int kLowestRendererOomScore = 300;
+const int kHighestRendererOomScore = 1000;
 #endif
 
 #if defined(OS_WIN)