Move ImportantFileWriter to base/. It now has two consumers, base/prefs and chrome/.

chrome/browser/bookmarks/bookmark_storage.h

Index: chrome/browser/bookmarks/bookmark_storage.h
diff --git a/chrome/browser/bookmarks/bookmark_storage.h b/chrome/browser/bookmarks/bookmark_storage.h
index ec93d0fa6393589125e7f6859dec0b07e33ceb05..b4f0d9da60d7f47616fe59c919035876bd539fd2 100644
--- a/chrome/browser/bookmarks/bookmark_storage.h
+++ b/chrome/browser/bookmarks/bookmark_storage.h
@@ -5,10 +5,10 @@
 #ifndef CHROME_BROWSER_BOOKMARKS_BOOKMARK_STORAGE_H_
 #define CHROME_BROWSER_BOOKMARKS_BOOKMARK_STORAGE_H_
 
+#include "base/files/important_file_writer.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/bookmarks/bookmark_index.h"
-#include "chrome/common/important_file_writer.h"
 
 class BookmarkModel;
 class BookmarkPermanentNode;
@@ -92,7 +92,7 @@ class BookmarkLoadDetails {
 // as notifying the BookmarkStorage every time the model changes.
 //
 // Internally BookmarkStorage uses BookmarkCodec to do the actual read/write.
-class BookmarkStorage : public ImportantFileWriter::DataSerializer,
+class BookmarkStorage : public base::ImportantFileWriter::DataSerializer,
                         public base::RefCountedThreadSafe<BookmarkStorage> {
  public:
   // Creates a BookmarkStorage for the specified model
@@ -128,7 +128,7 @@ class BookmarkStorage : public ImportantFileWriter::DataSerializer,
   BookmarkModel* model_;
 
   // Helper to write bookmark data safely.
-  ImportantFileWriter writer_;
+  base::ImportantFileWriter writer_;
 
   // See class description of BookmarkLoadDetails for details on this.
   scoped_ptr<BookmarkLoadDetails> details_;