Revert of Rate limit programmatic update checks for extensions

chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc

Index: chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
diff --git a/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc b/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
index 0bb2a193f5681af4805ad21e50cbe8fa041fae5a..1368740d7baab65f270949758e976e4f1d40675e 100644
--- a/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
+++ b/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
@@ -4,10 +4,8 @@
 
 #include "chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.h"
 
-#include <memory>
 #include <string>
 #include <utility>
-#include <vector>
 
 #include "base/location.h"
 #include "base/metrics/histogram.h"
@@ -25,14 +23,11 @@
 #include "chrome/browser/ui/browser_window.h"
 #include "components/update_client/update_query_params.h"
 #include "content/public/browser/notification_service.h"
-#include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/notification_types.h"
 #include "extensions/browser/warning_service.h"
 #include "extensions/browser/warning_set.h"
 #include "extensions/common/api/runtime.h"
-#include "extensions/common/constants.h"
-#include "net/base/backoff_entry.h"
 
 #if defined(OS_CHROMEOS)
 #include "chromeos/dbus/dbus_thread_manager.h"
@@ -60,67 +55,17 @@
 // disabled.
 const int kFastReloadCount = 5;
 
-// The policy we use for exponential backoff of update check requests.
-const net::BackoffEntry::Policy kBackoffPolicy = {
-    // num_errors_to_ignore
-    0,
-
-    // initial_delay_ms (note that we set 'always_use_initial_delay' to false
-    // below)
-    1000 * extensions::kDefaultUpdateFrequencySeconds,
-
-    // multiply_factor
-    1,
-
-    // jitter_factor
-    0.1,
-
-    // maximum_backoff_ms (-1 means no maximum)
-    -1,
-
-    // entry_lifetime_ms (-1 means never discard)
-    -1,
-
-    // always_use_initial_delay
-    false,
-};
-
-base::TickClock* g_test_clock = nullptr;
-
 }  // namespace
-
-struct ChromeRuntimeAPIDelegate::UpdateCheckInfo {
- public:
-  UpdateCheckInfo() {
-    if (g_test_clock)
-      backoff.reset(new net::BackoffEntry(&kBackoffPolicy, g_test_clock));
-    else
-      backoff.reset(new net::BackoffEntry(&kBackoffPolicy));
-  }
-
-  std::unique_ptr<net::BackoffEntry> backoff;
-  std::vector<UpdateCheckCallback> callbacks;
-};
 
 ChromeRuntimeAPIDelegate::ChromeRuntimeAPIDelegate(
     content::BrowserContext* context)
-    : browser_context_(context),
-      registered_for_updates_(false),
-      extension_registry_observer_(this) {
+    : browser_context_(context), registered_for_updates_(false) {
   registrar_.Add(this,
                  extensions::NOTIFICATION_EXTENSION_UPDATE_FOUND,
                  content::NotificationService::AllSources());
-  extension_registry_observer_.Add(
-      extensions::ExtensionRegistry::Get(browser_context_));
 }
 
 ChromeRuntimeAPIDelegate::~ChromeRuntimeAPIDelegate() {
-}
-
-// static
-void ChromeRuntimeAPIDelegate::set_tick_clock_for_tests(
-    base::TickClock* clock) {
-  g_test_clock = clock;
 }
 
 void ChromeRuntimeAPIDelegate::AddUpdateObserver(
@@ -207,20 +152,17 @@
   if (!updater) {
     return false;
   }
-
-  UpdateCheckInfo& info = update_check_info_[extension_id];
-
-  // If not enough time has elapsed, or we have 10 or more outstanding calls,
-  // return a status of throttled.
-  if (info.backoff->ShouldRejectRequest() || info.callbacks.size() >= 10) {
+  if (!updater->CheckExtensionSoon(
+          extension_id,
+          base::Bind(&ChromeRuntimeAPIDelegate::UpdateCheckComplete,
+                     base::Unretained(this),
+                     extension_id))) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::Bind(callback, UpdateCheckResult(true, kUpdateThrottled, "")));
   } else {
-    info.callbacks.push_back(callback);
-    updater->CheckExtensionSoon(
-        extension_id, base::Bind(&ChromeRuntimeAPIDelegate::UpdateCheckComplete,
-                                 base::Unretained(this), extension_id));
+    UpdateCallbackList& callbacks = pending_update_checks_[extension_id];
+    callbacks.push_back(callback);
   }
   return true;
 }
@@ -317,31 +259,11 @@
   }
 }
 
-void ChromeRuntimeAPIDelegate::OnExtensionInstalled(
-    content::BrowserContext* browser_context,
-    const Extension* extension,
-    bool is_update) {
-  if (!is_update)
-    return;
-  auto info = update_check_info_.find(extension->id());
-  if (info != update_check_info_.end()) {
-    info->second.backoff->Reset();
-  }
-}
-
 void ChromeRuntimeAPIDelegate::UpdateCheckComplete(
     const std::string& extension_id) {
   ExtensionSystem* system = ExtensionSystem::Get(browser_context_);
   ExtensionService* service = system->extension_service();
   const Extension* update = service->GetPendingExtensionUpdate(extension_id);
-  UpdateCheckInfo& info = update_check_info_[extension_id];
-
-  // We always inform the BackoffEntry of a "failure" here, because we only
-  // want to consider an update check request a success from a throttling
-  // standpoint once the extension goes on to actually update to a new
-  // version. See OnExtensionInstalled for where we reset the BackoffEntry.
-  info.backoff->InformOfRequest(false);
-
   if (update) {
     CallUpdateCallbacks(
         extension_id,
@@ -355,12 +277,12 @@
 void ChromeRuntimeAPIDelegate::CallUpdateCallbacks(
     const std::string& extension_id,
     const UpdateCheckResult& result) {
-  auto it = update_check_info_.find(extension_id);
-  if (it == update_check_info_.end())
-    return;
-  std::vector<UpdateCheckCallback> callbacks;
-  it->second.callbacks.swap(callbacks);
-  for (const auto& callback : callbacks) {
+  UpdateCallbackList callbacks = pending_update_checks_[extension_id];
+  pending_update_checks_.erase(extension_id);
+  for (UpdateCallbackList::const_iterator iter = callbacks.begin();
+       iter != callbacks.end();
+       ++iter) {
+    const UpdateCheckCallback& callback = *iter;
     callback.Run(result);
   }
 }