Unload the ScopedGaiaAuthExtension asynchronously.

If we don't do this, then we have a race condition between unloading
this extension, and trying to use it because we have manually
navigated to it.

BUG=460431

Committed: https://crrev.com/1805c4c5c4b5292cca51a54f379cde498db7238b
Cr-Commit-Position: refs/heads/master@{#318140}

Review URL: https://codereview.chromium.org/961443003

Cr-Commit-Position: refs/heads/master@{#320937}

chrome/browser/extensions/signin/gaia_auth_extension_loader.cc

@@ -8,6 +8,8 @@
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
 #include "chrome/browser/extensions/component_loader.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/signin/signin_promo.h"
@@ -86,7 +88,11 @@ void UnloadGaiaAuthExtension(BrowserContext* context) {
 namespace extensions {
 
 GaiaAuthExtensionLoader::GaiaAuthExtensionLoader(BrowserContext* context)
-    : browser_context_(context), load_count_(0), last_data_id_(0) {}
+    : browser_context_(context),
+      load_count_(0),
+      last_data_id_(0),
+      weak_ptr_factory_(this) {
+}
 
 GaiaAuthExtensionLoader::~GaiaAuthExtensionLoader() {
   DCHECK_EQ(0, load_count_);
@@ -98,6 +104,13 @@ void GaiaAuthExtensionLoader::LoadIfNeeded() {
   ++load_count_;
 }
 
+void GaiaAuthExtensionLoader::UnloadIfNeededAsync() {
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::Bind(&GaiaAuthExtensionLoader::UnloadIfNeeded,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
 void GaiaAuthExtensionLoader::UnloadIfNeeded() {
   --load_count_;
   if (load_count_ == 0) {

chrome/browser/extensions/signin/gaia_auth_extension_loader.h

@@ -9,6 +9,7 @@
 #include <string>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "extensions/browser/browser_context_keyed_api_factory.h"
 
 namespace content {
@@ -31,6 +32,7 @@ class GaiaAuthExtensionLoader : public BrowserContextKeyedAPI {
   void LoadIfNeeded();
   // Unload the gaia auth extension if no pending reference.
   void UnloadIfNeeded();
+  void UnloadIfNeededAsync();
 
   // Add a string data for gaia auth extension. Returns an ID that
   // could be used to get the data. All strings are cleared when gaia auth
@@ -65,6 +67,8 @@ class GaiaAuthExtensionLoader : public BrowserContextKeyedAPI {
   int last_data_id_;
   std::map<int, std::string> data_;
 
+  base::WeakPtrFactory<GaiaAuthExtensionLoader> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(GaiaAuthExtensionLoader);
 };
 

chrome/browser/extensions/signin/scoped_gaia_auth_extension.cc

@@ -20,5 +20,5 @@ ScopedGaiaAuthExtension::~ScopedGaiaAuthExtension() {
   extensions::GaiaAuthExtensionLoader* loader =
       extensions::GaiaAuthExtensionLoader::Get(browser_context_);
   if (loader)
-    loader->UnloadIfNeeded();
+    loader->UnloadIfNeededAsync();
 }