Clean up threading model of external extension providers

chrome/browser/extensions/external_registry_extension_loader_win.cc

Index: chrome/browser/extensions/external_registry_extension_loader_win.cc
diff --git a/chrome/browser/extensions/external_registry_extension_provider_win.cc b/chrome/browser/extensions/external_registry_extension_loader_win.cc
similarity index 52%
rename from chrome/browser/extensions/external_registry_extension_provider_win.cc
rename to chrome/browser/extensions/external_registry_extension_loader_win.cc
index 16b107ff9fdd3b040688442ac4eed3065f5dae12..7f2df55b57f15aac25a8b9c640c7ea6586165366 100644
--- a/chrome/browser/extensions/external_registry_extension_provider_win.cc
+++ b/chrome/browser/extensions/external_registry_extension_loader_win.cc
@@ -2,13 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/extensions/external_registry_extension_provider_win.h"
+#include "chrome/browser/extensions/external_registry_extension_loader_win.h"
 
 #include "base/file_path.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
+#include "base/values.h"
 #include "base/version.h"
 #include "base/win/registry.h"
+#include "chrome/browser/browser_thread.h"
+#include "chrome/browser/extensions/external_extension_provider_impl.h"
 
 namespace {
 
@@ -24,24 +27,21 @@ const wchar_t kRegistryExtensionPath[] = L"path";
 // Registry value of that key that defines the current version of the .crx file.
 const wchar_t kRegistryExtensionVersion[] = L"version";
 
-bool OpenKeyById(const std::string& id, base::win::RegKey *key) {
-  std::wstring key_path = ASCIIToWide(kRegistryExtensions);
-  key_path.append(L"\\");
-  key_path.append(ASCIIToWide(id));
-
-  return key->Open(kRegRoot, key_path.c_str(), KEY_READ);
-}
-
 }  // namespace
 
-ExternalRegistryExtensionProvider::ExternalRegistryExtensionProvider() {
+void ExternalRegistryExtensionLoader::StartLoading() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,
+      NewRunnableMethod(
+          this,
+          &ExternalRegistryExtensionLoader::LoadOnFileThread));
 }
 
-ExternalRegistryExtensionProvider::~ExternalRegistryExtensionProvider() {
-}
+void ExternalRegistryExtensionLoader::LoadOnFileThread() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  scoped_ptr<DictionaryValue> prefs(new DictionaryValue);
 
-void ExternalRegistryExtensionProvider::VisitRegisteredExtension(
-    Visitor* visitor) const {
   base::win::RegistryKeyIterator iterator(
       kRegRoot, ASCIIToWide(kRegistryExtensions).c_str());
   while (iterator.Valid()) {
@@ -57,19 +57,12 @@ void ExternalRegistryExtensionProvider::VisitRegisteredExtension(
           std::string id = WideToASCII(iterator.Name());
           StringToLowerASCII(&id);
 
-          scoped_ptr<Version> version;
-          version.reset(Version::GetVersionFromString(
-                            WideToASCII(extension_version)));
-          if (!version.get()) {
-            LOG(ERROR) << "Invalid version value " << extension_version
-                       << " for key " << key_path;
-            ++iterator;
-            continue;
-          }
-
-          FilePath path = FilePath::FromWStringHack(extension_path);
-          visitor->OnExternalExtensionFileFound(id, version.get(), path,
-                                                Extension::EXTERNAL_REGISTRY);
+          prefs->SetString(
+              id + "." + ExternalExtensionProviderImpl::kExternalVersion,
+              WideToASCII(extension_version));
+          prefs->SetString(
+              id + "." + ExternalExtensionProviderImpl::kExternalCrx,
+              extension_path);
         } else {
           // TODO(erikkay): find a way to get this into about:extensions
           LOG(ERROR) << "Missing value " << kRegistryExtensionVersion
@@ -83,33 +76,11 @@ void ExternalRegistryExtensionProvider::VisitRegisteredExtension(
     }
     ++iterator;
   }
-}
-
-
-bool ExternalRegistryExtensionProvider::HasExtension(
-    const std::string& id) const {
-  base::win::RegKey key;
-  return OpenKeyById(id, &key);
-}
-
-bool ExternalRegistryExtensionProvider::GetExtensionDetails(
-    const std::string& id,
-    Extension::Location* location,
-    scoped_ptr<Version>* version) const  {
-  base::win::RegKey key;
-  if (!OpenKeyById(id, &key))
-    return false;
-
-  std::wstring extension_version;
-  if (!key.ReadValue(kRegistryExtensionVersion, &extension_version))
-    return false;
-
-  if (version) {
-    version->reset(Version::GetVersionFromString(
-                       WideToASCII(extension_version)));
-  }
 
-  if (location)
-    *location = Extension::EXTERNAL_REGISTRY;
-  return true;
+  prefs_.reset(prefs.release());
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      NewRunnableMethod(
+          this,
+          &ExternalRegistryExtensionLoader::LoadFinished));
 }