Use gpu::Mailbox in IPCs instead of std::string

content/renderer/browser_plugin/browser_plugin_manager_impl.h

Index: content/renderer/browser_plugin/browser_plugin_manager_impl.h
diff --git a/content/renderer/browser_plugin/browser_plugin_manager_impl.h b/content/renderer/browser_plugin/browser_plugin_manager_impl.h
index 24964742b77f9e2c4765d93258bd34e060f6a981..b8505e3a25d4a6249cee1c8de6e2146c5ae895b2 100644
--- a/content/renderer/browser_plugin/browser_plugin_manager_impl.h
+++ b/content/renderer/browser_plugin/browser_plugin_manager_impl.h
@@ -16,6 +16,10 @@ namespace gfx {
 class Point;
 }
 
+namespace gpu {
+struct Mailbox;
+}
+
 namespace content {
 
 class BrowserPluginManagerImpl : public BrowserPluginManager {
@@ -46,7 +50,7 @@ class BrowserPluginManagerImpl : public BrowserPluginManager {
   void OnUnhandledSwap(const IPC::Message& message,
                        int instance_id,
                        const gfx::Size& size,
-                       std::string mailbox_name,
+                       gpu::Mailbox mailbox_name,
                        int gpu_route_id,
                        int gpu_host_id);