Fix a rare crash in ExtensionResourcesJob::ResolvePath.

Use PostTaskAndReplyWithReply() which guarantees task and reply closures will be deleted on the correct thread, also use WeakPtr to make the task cancelable.

BUG=246977

Review URL: https://chromiumcodereview.appspot.com/16124016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@205917 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 24 insertions, 20 deletions

diff --git a/chrome/browser/extensions/extension_resource_protocols.cc b/chrome/browser/extensions/extension_resource_protocols.cc
index 03f2a67..565b08b 100644
--- a/chrome/browser/extensions/extension_resource_protocols.cc
+++ b/chrome/browser/extensions/extension_resource_protocols.cc
@@ -5,7 +5,9 @@
 #include "chrome/browser/extensions/extension_resource_protocols.h"
 
 #include "base/files/file_path.h"
+#include "base/memory/weak_ptr.h"
 #include "base/path_service.h"
+#include "base/threading/thread_checker.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_file_util.h"
 #include "content/public/browser/browser_thread.h"
@@ -13,12 +15,18 @@
 
 namespace {
 
+base::FilePath ResolvePath(const GURL& url) {
+  base::FilePath root_path;
+  PathService::Get(chrome::DIR_RESOURCES_EXTENSION, &root_path);
+  return extension_file_util::ExtensionResourceURLToFilePath(url, root_path);
+}
+
 class ExtensionResourcesJob : public net::URLRequestFileJob {
  public:
   ExtensionResourcesJob(net::URLRequest* request,
                         net::NetworkDelegate* network_delegate)
     : net::URLRequestFileJob(request, network_delegate, base::FilePath()),
-      thread_id_(content::BrowserThread::UI) {
+      weak_ptr_factory_(this) {
   }
 
   virtual void Start() OVERRIDE;
@@ -26,33 +34,29 @@ class ExtensionResourcesJob : public net::URLRequestFileJob {
  protected:
   virtual ~ExtensionResourcesJob() {}
 
-  void ResolvePath();
-  void ResolvePathDone();
+  void ResolvePathDone(const base::FilePath& resolved_path);
 
  private:
-  content::BrowserThread::ID thread_id_;
+  base::WeakPtrFactory<ExtensionResourcesJob> weak_ptr_factory_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionResourcesJob);
 };
 
 void ExtensionResourcesJob::Start() {
-  bool result =
-      content::BrowserThread::GetCurrentThreadIdentifier(&thread_id_);
-  CHECK(result) << "Can not get thread id.";
-  content::BrowserThread::PostTask(
+  DCHECK(thread_checker_.CalledOnValidThread());
+  content::BrowserThread::PostTaskAndReplyWithResult(
       content::BrowserThread::FILE, FROM_HERE,
-      base::Bind(&ExtensionResourcesJob::ResolvePath, this));
-}
-
-void ExtensionResourcesJob::ResolvePath() {
-  base::FilePath root_path;
-  PathService::Get(chrome::DIR_RESOURCES_EXTENSION, &root_path);
-  file_path_ = extension_file_util::ExtensionResourceURLToFilePath(
-      request()->url(), root_path);
-  content::BrowserThread::PostTask(
-      thread_id_, FROM_HERE,
-      base::Bind(&ExtensionResourcesJob::ResolvePathDone, this));
+      base::Bind(&ResolvePath, request()->url()),
+      base::Bind(&ExtensionResourcesJob::ResolvePathDone,
+          weak_ptr_factory_.GetWeakPtr()));
 }
 
-void ExtensionResourcesJob::ResolvePathDone() {
+void ExtensionResourcesJob::ResolvePathDone(
+    const base::FilePath& resolved_path) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  file_path_ = resolved_path;
   net::URLRequestFileJob::Start();
 }