Can now adjust the number of retries before the blacklist is disabled.

chrome/browser/chrome_elf_init_win.cc

Index: chrome/browser/chrome_elf_init_win.cc
diff --git a/chrome/browser/chrome_elf_init_win.cc b/chrome/browser/chrome_elf_init_win.cc
index 042f3d1a4063383134df0cf06f5f238598af6837..71d54d41f33db4a18d8ed61a9325fe2b768f3333 100644
--- a/chrome/browser/chrome_elf_init_win.cc
+++ b/chrome/browser/chrome_elf_init_win.cc
@@ -18,6 +18,8 @@
 const char kBrowserBlacklistTrialName[] = "BrowserBlacklist";
 const char kBrowserBlacklistTrialDisabledGroupName[] = "NoBlacklist";
 
+const DWORD kBeaconAttempts = 2;
+
 namespace {
 
 // How long to wait, in seconds, before reporting for the second (and last
@@ -103,6 +105,17 @@ void InitializeChromeElf() {
       base::TimeDelta::FromSeconds(kBlacklistReportingDelaySec));
 }
 
+void GetBlacklistFailedCount(DWORD* failed_count) {
+  base::win::RegKey key(HKEY_CURRENT_USER,
+                        blacklist::kRegistryBeaconPath,
+                        KEY_QUERY_VALUE | KEY_SET_VALUE);
+  bool count_exists = key.HasValue(blacklist::kBeaconFailedCount);
+  if (!count_exists)
+    key.WriteValue(blacklist::kBeaconFailedCount, static_cast<DWORD>(0));
+
+  key.ReadValueDW(blacklist::kBeaconFailedCount, failed_count);
+}
+
 void BrowserBlacklistBeaconSetup() {
   base::win::RegKey blacklist_registry_key(HKEY_CURRENT_USER,
                                            blacklist::kRegistryBeaconPath,
@@ -118,6 +131,16 @@ void BrowserBlacklistBeaconSetup() {
 
   if (blacklist_state == blacklist::BLACKLIST_ENABLED) {
     RecordBlacklistSetupEvent(BLACKLIST_SETUP_RAN_SUCCESSFULLY);
+
+    // The blacklist was enabled successfully so we record the event (along with
+    // the number of failed previous attempts) and reset the failure count.
+    DWORD failed_attempt_count = 0;
+    GetBlacklistFailedCount(&failed_attempt_count);
+    UMA_HISTOGRAM_COUNTS("Blacklist.RetryWorked", failed_attempt_count);
+
+    blacklist_registry_key.WriteValue(blacklist::kBeaconFailedCount,
+                                      static_cast<DWORD>(0));
+
   } else {
     switch (blacklist_state) {
       case blacklist::BLACKLIST_SETUP_RUNNING:
@@ -131,11 +154,24 @@ void BrowserBlacklistBeaconSetup() {
         break;
     }
 
-    // Since some part of the blacklist failed, mark it as disabled
-    // for this version.
+    // Some part of the blacklist failed.  If this has occured some minimum
+    // number of times in a row we give up, disable it, and record the
+    // disabling event with UMA.
     if (blacklist_state != blacklist::BLACKLIST_DISABLED) {
-      blacklist_registry_key.WriteValue(blacklist::kBeaconState,
-                                        blacklist::BLACKLIST_DISABLED);
+      DWORD failed_attempt_count = 0;
+      GetBlacklistFailedCount(&failed_attempt_count);
+      failed_attempt_count = failed_attempt_count + 1;
+
+      if (failed_attempt_count >= kBeaconAttempts) {
+        blacklist_registry_key.WriteValue(blacklist::kBeaconState,
+                                          blacklist::BLACKLIST_DISABLED);
+        UMA_HISTOGRAM_COUNTS("Blacklist.Disabled", true);
+      } else {
+        blacklist_registry_key.WriteValue(blacklist::kBeaconFailedCount,
+                                          failed_attempt_count);
+        blacklist_registry_key.WriteValue(blacklist::kBeaconState,
+                                          blacklist::BLACKLIST_ENABLED);
+      }
     }
   }
 
@@ -145,7 +181,8 @@ void BrowserBlacklistBeaconSetup() {
                                    &blacklist_version);
 
   if (blacklist_version != TEXT(CHROME_VERSION_STRING)) {
-    // The blacklist hasn't been enabled for this version yet, so enable it.
+    // The blacklist hasn't been enabled for this version yet, so enable it
+    // and reset the failure count to zero.
     LONG set_version = blacklist_registry_key.WriteValue(
         blacklist::kBeaconVersion,
         TEXT(CHROME_VERSION_STRING));
@@ -154,6 +191,9 @@ void BrowserBlacklistBeaconSetup() {
         blacklist::kBeaconState,
         blacklist::BLACKLIST_ENABLED);
 
+    blacklist_registry_key.WriteValue(blacklist::kBeaconFailedCount,
+                                      static_cast<DWORD>(0));
+
     // Only report the blacklist as getting setup when both registry writes
     // succeed, since otherwise the blacklist wasn't properly setup.
     if (set_version == ERROR_SUCCESS && set_state == ERROR_SUCCESS)