Parameterize the PrefService that AutofillDownloadManager uses.

components/autofill/core/browser/autofill_download.h

Index: components/autofill/core/browser/autofill_download.h
diff --git a/components/autofill/core/browser/autofill_download.h b/components/autofill/core/browser/autofill_download.h
index bba1d7197629883d732c07f2c56620984c8faee2..23d2fad7affd58e3e6598ef80bae2036751673e3 100644
--- a/components/autofill/core/browser/autofill_download.h
+++ b/components/autofill/core/browser/autofill_download.h
@@ -18,6 +18,8 @@
 #include "components/autofill/core/browser/autofill_type.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
+class PrefService;
+
 namespace content {
 class BrowserContext;
 }  // namespace content
@@ -62,8 +64,10 @@ class AutofillDownloadManager : public net::URLFetcherDelegate {
     virtual ~Observer() {}
   };
 
+  // |context| and |pref_service| must outlive this instance.
   // |observer| - observer to notify on successful completion or error.
   AutofillDownloadManager(content::BrowserContext* context,
+                          PrefService* pref_service,
                           Observer* observer);
   virtual ~AutofillDownloadManager();
 
@@ -136,6 +140,10 @@ class AutofillDownloadManager : public net::URLFetcherDelegate {
   // constructor.  Must not be null.
   content::BrowserContext* const browser_context_;  // WEAK
 
+  // The pointer value is const, so this can only be set in the
+  // constructor.  Must not be null, and must outlive this instance.

[Ilya Sherman, 2013/11/05 00:17:04]

nit: No need to document what "const" means -- that should be clear from the
code to anyone sufficiently familiar with C++, and easy to research to anyone
who doesn't quite remember what "const" means in this context.  Please instead
document the role or purpose of this data member.  (I see that this was probably
copied from the above and below comments, but IMO those should be shortened as
well; this really is a language detail that ought to be safe to assume as common
knowledge.)

[blundell, 2013/11/05 15:26:54]

Done.

+  PrefService* const pref_service_;  // WEAK
+
   // The observer to notify when server predictions are successfully received.
   // The pointer value is const, so this can only be set in the constructor.
   // Must not be null.