history: Remove unused bookmark constant.

chrome/browser/history/in_memory_history_backend.cc

Index: chrome/browser/history/in_memory_history_backend.cc
diff --git a/chrome/browser/history/in_memory_history_backend.cc b/chrome/browser/history/in_memory_history_backend.cc
index 5eabb8825ea3df1c9455390a0e73ce89ef47376c..e69009b7cad4e4bc932952b59afaf7393e6df95c 100644
--- a/chrome/browser/history/in_memory_history_backend.cc
+++ b/chrome/browser/history/in_memory_history_backend.cc
@@ -22,10 +22,6 @@
 
 namespace history {
 
-// If a page becomes starred we use this id in place of the real starred id.
-// See note in OnURLsStarred.
-static const StarID kBogusStarredID = 0x0FFFFFFF;
-
 InMemoryHistoryBackend::InMemoryHistoryBackend()
     : profile_(NULL) {
 }