Make SQL in DownloadDatabase SQLite pre 3.8.3 compatible

components/history/core/browser/download_database.cc

Index: components/history/core/browser/download_database.cc
diff --git a/components/history/core/browser/download_database.cc b/components/history/core/browser/download_database.cc
index 8430305ebeb002b339c298df8c3116f1bfbdc238..19f37ffb304821af3377cf9adc631452f44d1d45 100644
--- a/components/history/core/browser/download_database.cc
+++ b/components/history/core/browser/download_database.cc
@@ -239,14 +239,16 @@ bool DownloadDatabase::MigrateHashHttpMethodAndGenerateGuids() {
   // base::GenerateGUID() and are considered valid by all known consumers. Hence
   // no additional migration logic is being introduced to fix those GUIDs.
   const char kMigrateGuidsQuery[] =
-      "UPDATE downloads SET guid = printf"
-      "(\"%08X-%s-4%s-%01X%s-%s\","
-      " id,"
-      " hex(randomblob(2)),"
-      " substr(hex(randomblob(2)),2),"
-      " (8 | (random() & 3)),"
-      " substr(hex(randomblob(2)),2),"
-      " hex(randomblob(6)))";
+      "UPDATE downloads SET guid = "
+      "substr(hex(char( id>>28)    ),2) || substr(hex(char((id>>24)&15)),2) || "

[Scott Hess - ex-Googler, 2016/04/21 02:32:55]

Since SQLite integers are 64-bit, I'd throw in the &15 just for the heck of it.

+      "substr(hex(char((id>>20)&15)),2) || substr(hex(char((id>>16)&15)),2) || "
+      "substr(hex(char((id>>12)&15)),2) || substr(hex(char((id>> 8)&15)),2) || "
+      "substr(hex(char((id>> 4)&15)),2) || substr(hex(char( id     &15)),2) || "
+      "'-' || hex(randomblob(2)) || "
+      "'-4' || substr(hex(randomblob(2)),2) || "
+      "'-' || substr('89AB',1+(random()&3),1) || "
+      "       substr(hex(randomblob(2)),2) || "
+      "'-' || hex(randomblob(6))";

[Scott Hess - ex-Googler, 2016/04/21 02:32:55]

Wow.  I assume you have golden tests for this so you'd notice it breaking?

Since generally the majority of the real work is in reading and writing the file
itself, not the processing, and this is a migration anyhow, I wonder if this
wouldn't be more easily done with something like:
  sql::Statement s(GetCached("SELECT id FROM downloads"));
  sql::Statement u(GetCached("UPDATE downloads SET guid = ? WHERE id = ?"));
  while (s.Step()) {
    u.BindBlob(0, MakeGuid(s.ColumnInt(0)));
    u.BindInteger(1, s.ColumnInt(0));
  }

   return GetDB().Execute(kMigrateGuidsQuery);
 }