Add a whitelist for the new binary download protection.

chrome/browser/safe_browsing/safe_browsing_service.cc

Index: chrome/browser/safe_browsing/safe_browsing_service.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.cc b/chrome/browser/safe_browsing/safe_browsing_service.cc
index d640f1c3ffb52bfc71203a2eaea330a7f0b05925..69ba5f3ab168e2d111426dacba8a1c32de7d872b 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_service.cc
@@ -161,6 +161,7 @@ SafeBrowsingService::SafeBrowsingService()
       enabled_(false),
       enable_download_protection_(false),
       enable_csd_whitelist_(false),
+      enable_download_whitelist_(false),
       update_in_progress_(false),
       database_update_in_progress_(false),
       closing_database_(false),
@@ -687,7 +688,8 @@ SafeBrowsingDatabase* SafeBrowsingService::GetDatabase() {
 
   SafeBrowsingDatabase* database =
       SafeBrowsingDatabase::Create(enable_download_protection_,
-                                   enable_csd_whitelist_);
+                                   enable_csd_whitelist_,
+                                   enable_download_whitelist_);
 
   database->Init(path);
   {
@@ -907,6 +909,14 @@ void SafeBrowsingService::Start() {
          local_state->GetBoolean(prefs::kMetricsReportingEnabled))));
 #endif
 
+  const PrefService::Preference* pref = (local_state ?
+    local_state->FindPreference(
+        prefs::kSafeBrowsingOptinDownloadProtectionEnabled) : NULL);
+  bool pref_value = false;
+  enable_download_whitelist_ = (pref &&
+                                pref->GetValue()->GetAsBoolean(&pref_value) &&
+                                pref_value);

[mattm, 2011/09/13 00:29:02]

Oh, thinking about this a bit harder, this isn't quite right. 
Profile::RegisterUserPrefs is registering the pref in the profile prefs, not the
local state prefs.   You could register it in local_state, but for the
multi-profile world it would be best to keep it registered in the profile.  

That means you'd have to either change the code to keep track of whether any
loaded profiles have it enabled (similar to the way safebrowsing itself is
enabled) or just always update the download whitelist.

[noelutz, 2011/09/13 20:35:39]

That does seem a bit complicated.  How about we always update that whitelist
since it is so small?  Also, we're talking about making that feature an opt-out
like SafeBrowsing so most people will have it enabled.

[mattm, 2011/09/14 01:15:18]

Yeah, just always updating it sounds fine.

+
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       NewRunnableMethod(