Relanding this as the previous attempt failed due to build errors.

webkit/plugins/plugin_constants.h

Index: webkit/plugins/plugin_constants.h
===================================================================
--- webkit/plugins/plugin_constants.h	(revision 200310)
+++ webkit/plugins/plugin_constants.h	(working copy)
@@ -6,20 +6,19 @@
 #define WEBKIT_PLUGINS_PLUGIN_CONSTANTS_H_
 
 #include "base/basictypes.h"
-#include "webkit/plugins/webkit_plugins_export.h"
 
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginName[];
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginSwfMimeType[];
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginSwfExtension[];
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginSwfDescription[];
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginSplMimeType[];
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginSplExtension[];
-WEBKIT_PLUGINS_EXPORT extern const char kFlashPluginSplDescription[];
+extern const char kFlashPluginName[];
+extern const char kFlashPluginSwfMimeType[];
+extern const char kFlashPluginSwfExtension[];
+extern const char kFlashPluginSwfDescription[];
+extern const char kFlashPluginSplMimeType[];
+extern const char kFlashPluginSplExtension[];
+extern const char kFlashPluginSplDescription[];
 
 // The maximum plugin width and height.
-WEBKIT_PLUGINS_EXPORT extern const uint16 kMaxPluginSideLength;
+extern const uint16 kMaxPluginSideLength;
 // The maximum plugin size, defined as the number of pixels occupied by the
 // plugin.
-WEBKIT_PLUGINS_EXPORT extern const uint32 kMaxPluginSize;
+extern const uint32 kMaxPluginSize;
 
 #endif  // WEBKIT_PLUGINS_PLUGIN_CONSTANTS_H_