Eliminate the archived history database and clean up related code.

chrome/browser/history/url_database.cc

Index: chrome/browser/history/url_database.cc
diff --git a/chrome/browser/history/url_database.cc b/chrome/browser/history/url_database.cc
index 840a382e1db5009e13e32a215b6e716dc00e64b2..1022eb29ac1796daec0e2d3a1b5334713ebcf875 100644
--- a/chrome/browser/history/url_database.cc
+++ b/chrome/browser/history/url_database.cc
@@ -218,6 +218,7 @@ bool URLDatabase::CommitTemporaryURLTable() {
   // HistoryBackend::DeleteAllHistory() for more information on how this works
   // and why it does what it does.
   //
+  // TODO(engedy): The following is not true any longer. Revise this part.
   // Note that the main database overrides this to additionally create the
   // supplimentary indices that the archived database doesn't need.
 
@@ -231,10 +232,8 @@ bool URLDatabase::CommitTemporaryURLTable() {
     return false;
   }
 
-  // Create the index over URLs. This is needed for the main, in-memory, and
-  // archived databases, so we always do it. The supplimentary indices used by
-  // the main database are not created here. When deleting all history, they
-  // are created by HistoryDatabase::RecreateAllButStarAndURLTables().

[engedy, 2014/04/16 18:08:10]

Note: Removing this as there is no CreateSupplimentaryURLIndices() anymore.

Interestingly, RecreateAllTablesButURL() had not always been called after this
function, so there had been cases when the FavIcon index would not have been
created.

However, this is no longer an issue, as we only have a single index on the URLs
table, which is created by CreateMainURLIndex().

+  // Create the index over URLs. This is currently needed for both the main and
+  // the in-memory databases, so we always do it.
   CreateMainURLIndex();
 
   return true;