Fix race condition in WebstoreInstallHelper

chrome/browser/extensions/webstore_install_helper.cc

Index: chrome/browser/extensions/webstore_install_helper.cc
diff --git a/chrome/browser/extensions/webstore_install_helper.cc b/chrome/browser/extensions/webstore_install_helper.cc
index 948d9954134fe6b38718be0cd34471830942c63a..4ad14e9ce3526cd8c3cde1ebbae64dcde5eef8ea 100644
--- a/chrome/browser/extensions/webstore_install_helper.cc
+++ b/chrome/browser/extensions/webstore_install_helper.cc
@@ -51,6 +51,15 @@ WebstoreInstallHelper::~WebstoreInstallHelper() {}
 void WebstoreInstallHelper::Start() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&WebstoreInstallHelper::StartWorkOnIOThread, this));
+}
+
+void WebstoreInstallHelper::StartWorkOnIOThread() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
   if (icon_url_.is_empty()) {
     icon_decode_complete_ = true;
   } else {
@@ -64,14 +73,6 @@ void WebstoreInstallHelper::Start() {
         net::LOAD_DO_NOT_SAVE_COOKIES | net::LOAD_DO_NOT_SEND_COOKIES);
   }
 
-  BrowserThread::PostTask(
-      BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(&WebstoreInstallHelper::StartWorkOnIOThread, this));
-}
-
-void WebstoreInstallHelper::StartWorkOnIOThread() {
-  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   utility_host_ = UtilityProcessHost::Create(
       this, base::ThreadTaskRunnerHandle::Get().get())->AsWeakPtr();
   utility_host_->SetName(l10n_util::GetStringUTF16(
@@ -95,7 +96,7 @@ bool WebstoreInstallHelper::OnMessageReceived(const IPC::Message& message) {
 
 void WebstoreInstallHelper::OnFetchComplete(const GURL& url,
                                             const SkBitmap* image) {
-  CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   // OnFetchComplete should only be called as icon_fetcher_ delegate to avoid
   // unbalanced Release().
   CHECK(icon_fetcher_.get());
@@ -108,11 +109,8 @@ void WebstoreInstallHelper::OnFetchComplete(const GURL& url,
     parse_error_ = Delegate::ICON_ERROR;
   }
   icon_fetcher_.reset();
-  BrowserThread::PostTask(
-      BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(&WebstoreInstallHelper::ReportResultsIfComplete, this));
-  Release();  // Balanced in Start().
+  Release();  // Balanced in StartWorkOnIOThread().
+  ReportResultsIfComplete();
 }
 
 void WebstoreInstallHelper::OnJSONParseSucceeded(