Move ChromeRequirementsChecker to //extensions as a PreloadCheck

extensions/browser/requirements_checker.cc

Index: extensions/browser/requirements_checker.cc
diff --git a/chrome/browser/extensions/chrome_requirements_checker.cc b/extensions/browser/requirements_checker.cc
similarity index 39%
rename from chrome/browser/extensions/chrome_requirements_checker.cc
rename to extensions/browser/requirements_checker.cc
index 3aeacef8b262a1024659b832aca336e36abf85b3..83535e5cb22a8ff19301789163843a56e00c80e2 100644
--- a/chrome/browser/extensions/chrome_requirements_checker.cc
+++ b/extensions/browser/requirements_checker.cc
@@ -1,89 +1,85 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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 "chrome/browser/extensions/chrome_requirements_checker.h"
+#include "extensions/browser/requirements_checker.h"
 
 #include "base/bind.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
-#include "chrome/grit/generated_resources.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/gpu_feature_checker.h"
 #include "extensions/common/extension.h"
-#include "extensions/common/manifest.h"
 #include "extensions/common/manifest_handlers/requirements_info.h"
+#include "extensions/strings/grit/extensions_strings.h"
 #include "gpu/config/gpu_feature_type.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace extensions {
 
-ChromeRequirementsChecker::ChromeRequirementsChecker()
-    : pending_requirement_checks_(0), weak_ptr_factory_(this) {
-}
+RequirementsChecker::RequirementsChecker(
+    scoped_refptr<const Extension> extension)
+    : PreloadCheck(extension), weak_ptr_factory_(this) {}
 
-ChromeRequirementsChecker::~ChromeRequirementsChecker() {
-}
+RequirementsChecker::~RequirementsChecker() {}
 
-void ChromeRequirementsChecker::Check(
-    const scoped_refptr<const Extension>& extension,
-    const RequirementsCheckedCallback& callback) {
+void RequirementsChecker::Start(ResultCallback callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
-  callback_ = callback;
   const RequirementsInfo& requirements =
-      RequirementsInfo::GetRequirements(extension.get());
+      RequirementsInfo::GetRequirements(extension());
 
-  if (requirements.npapi) {
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
-    errors_.push_back(
-        l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
+  if (requirements.npapi)
+    errors_.insert(NPAPI_NOT_SUPPORTED);
 #endif
-  }
 
-  if (requirements.window_shape) {
 #if !defined(USE_AURA)
-    errors_.push_back(
-        l10n_util::GetStringUTF8(IDS_EXTENSION_WINDOW_SHAPE_NOT_SUPPORTED));
+  if (requirements.window_shape)
+    errors_.insert(WINDOW_SHAPE_NOT_SUPPORTED);
 #endif
-  }
 
   if (requirements.webgl) {
-    ++pending_requirement_checks_;
+    callback_ = std::move(callback);
     webgl_checker_ = content::GpuFeatureChecker::Create(
         gpu::GPU_FEATURE_TYPE_ACCELERATED_WEBGL,
-        base::Bind(&ChromeRequirementsChecker::SetWebGLAvailability,
+        base::Bind(&RequirementsChecker::OnGetWebGLAvailability,
                    weak_ptr_factory_.GetWeakPtr()));
-  }
-
-  if (pending_requirement_checks_ == 0) {
-    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
-                                     base::Bind(callback_, errors_));
-    // Reset the callback so any ref-counted bound parameters will get released.
-    callback_.Reset();
-    return;
-  }
-  // Running the GPU checkers down here removes any race condition that arises
-  // from the use of pending_requirement_checks_.
-  if (webgl_checker_.get())
     webgl_checker_->CheckGpuFeatureAvailability();
+  } else {
+    std::move(callback).Run(errors_);
+  }
 }
 
-void ChromeRequirementsChecker::SetWebGLAvailability(bool available) {
-  if (!available) {
-    errors_.push_back(
+base::string16 RequirementsChecker::GetErrorMessage() const {
+  // Join the error messages into one string.
+  std::vector<std::string> messages;
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+  if (errors_.count(NPAPI_NOT_SUPPORTED)) {
+    messages.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
+  }
+#endif
+  if (errors_.count(WEBGL_NOT_SUPPORTED)) {
+    messages.push_back(
         l10n_util::GetStringUTF8(IDS_EXTENSION_WEBGL_NOT_SUPPORTED));
   }
-  MaybeRunCallback();
+#if !defined(USE_AURA)
+  if (errors_.count(WINDOW_SHAPE_NOT_SUPPORTED)) {
+    messages.push_back(
+        l10n_util::GetStringUTF8(IDS_EXTENSION_WINDOW_SHAPE_NOT_SUPPORTED));
+  }
+#endif
+
+  return base::UTF8ToUTF16(base::JoinString(messages, " "));
 }
 
-void ChromeRequirementsChecker::MaybeRunCallback() {
-  if (--pending_requirement_checks_ == 0) {
-    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
-                                     base::Bind(callback_, errors_));
-    // Reset the callback so any ref-counted bound parameters will get released.
-    callback_.Reset();
-    errors_.clear();
-  }
+void RequirementsChecker::OnGetWebGLAvailability(bool available) {

[Devlin, 2017/04/04 01:27:43]

OnGot...?  OnDetermined...? OnChecked...?  Something past-tense.

[michaelpg, 2017/04/04 21:45:40]

Made it less event-y and more imperativey.

+  DCHECK(callback_);
+  if (!available)
+    errors_.insert(WEBGL_NOT_SUPPORTED);
+  std::move(callback_).Run(errors_);
 }
 
 }  // namespace extensions