PreloadCheckGroup for managing multiple extension PreloadChecks

extensions/browser/preload_check_group.cc

Index: extensions/browser/preload_check_group.cc
diff --git a/extensions/browser/preload_check_group.cc b/extensions/browser/preload_check_group.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d777d521f85a7cb15798374e88cc2221a4a6576c
--- /dev/null
+++ b/extensions/browser/preload_check_group.cc
@@ -0,0 +1,85 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/browser/preload_check_group.h"
+
+#include "base/callback_helpers.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace extensions {
+
+PreloadCheckGroup::PreloadCheckGroup(scoped_refptr<Extension> extension,
+                                     const std::vector<PreloadCheck*>& checks,
+                                     bool fail_fast)
+    : PreloadCheck(extension),
+      fail_fast_(fail_fast),
+      running_checks_(0),
+      checks_(checks),
+      weak_ptr_factory_(this) {}
+
+PreloadCheckGroup::~PreloadCheckGroup() {}
+
+/*
+void PreloadCheckGroup::AddCheck(PreloadCheck* check) {
+  DCHECK(running_checks_ == 0);
+  checks_.push_back(check);
+}
+*/
+
+void PreloadCheckGroup::Start(ResultCallback callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  DCHECK(running_checks_ == 0);
+  DCHECK(!callback.is_null());
+
+  callback_ = std::move(callback);
+
+  running_checks_ = checks_.size();
+  for (auto* check : checks_) {
+    check->Start(base::Bind(&PreloadCheckGroup::OnCheckComplete,
+                            weak_ptr_factory_.GetWeakPtr(), check));
+    // Synchronous checks may fail immediately.
+    if (running_checks_ == 0)
+      return;
+  }
+}
+
+/*
+base::string16 PreloadCheckGroup::GetErrorMessage() const {
+  DCHECK_NE(error, nullptr);
+  if (error_.empty())
+    return false;
+
+  *error = error_;
+  return true;
+}
+*/
+
+void PreloadCheckGroup::OnCheckComplete(PreloadCheck* check, Errors errors) {
+  if (errors.size()) {
+    errors_.insert(errors.begin(), errors.end());
+    /*
+    if (error_.empty())
+      error_ = check->GetErrorMessage();
+      */
+  }
+  running_checks_--;
+  MaybeInvokeCallback();
+}
+
+void PreloadCheckGroup::MaybeInvokeCallback() {
+  if (callback_.is_null())
+    return;
+
+  // Invoke callback if all checks are complete or there was at least one
+  // failure and |fail_fast_| is true.
+  if (running_checks_ == 0 || (errors_.size() && fail_fast_)) {
+    // If we are failing fast, discard any pending results.
+    weak_ptr_factory_.InvalidateWeakPtrs();
+    running_checks_ = 0;
+
+    base::ResetAndReturn(&callback_).Run(errors_);
+  }
+}
+
+}  // namespace extensions