Use an explicitly-sized int type across the IPC boundary.

content/browser/renderer_host/render_widget_helper.cc

Index: content/browser/renderer_host/render_widget_helper.cc
diff --git a/content/browser/renderer_host/render_widget_helper.cc b/content/browser/renderer_host/render_widget_helper.cc
index d244da75383ef3f8d0f037ce8d2166579cab5b77..0321702723fe8f8c421ed11f8235df0321899ae9 100644
--- a/content/browser/renderer_host/render_widget_helper.cc
+++ b/content/browser/renderer_host/render_widget_helper.cc
@@ -348,8 +348,9 @@ TransportDIB* RenderWidgetHelper::MapTransportDIB(TransportDIB::Id dib_id) {
   return TransportDIB::Map(fd);
 }
 
-void RenderWidgetHelper::AllocTransportDIB(
-    size_t size, bool cache_in_browser, TransportDIB::Handle* result) {
+void RenderWidgetHelper::AllocTransportDIB(uint32 size,
+                                           bool cache_in_browser,
+                                           TransportDIB::Handle* result) {
   scoped_ptr<base::SharedMemory> shared_memory(new base::SharedMemory());
   if (!shared_memory->CreateAnonymous(size)) {
     result->fd = -1;