Add FilePath to base namespace.

chrome/browser/history/in_memory_database.h

Index: chrome/browser/history/in_memory_database.h
diff --git a/chrome/browser/history/in_memory_database.h b/chrome/browser/history/in_memory_database.h
index 17cb6f16e4d1e3236d779e39d8c53cd3bf36aabe..b729686389b1355eabf083a95661b0ee14cf65e8 100644
--- a/chrome/browser/history/in_memory_database.h
+++ b/chrome/browser/history/in_memory_database.h
@@ -9,7 +9,9 @@
 #include "chrome/browser/history/url_database.h"
 #include "sql/connection.h"
 
+namespace base {
 class FilePath;
+}
 
 namespace history {
 
@@ -28,7 +30,7 @@ class InMemoryDatabase : public URLDatabase {
   // file. Conceptually, the InMemoryHistoryBackend should do the populating
   // after this object does some common initialization, but that would be
   // much slower.
-  bool InitFromDisk(const FilePath& history_name);
+  bool InitFromDisk(const base::FilePath& history_name);
 
  protected:
   // Implemented for URLDatabase.