Reland r63578 - Release ChromeURLRequestContextGetters' references on IO thread shutdown."

Should be safe to reland after r65479.

BUG=58859
TEST=none

Review URL: http://codereview.chromium.org/4672005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@65504 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 26 insertions, 5 deletions

diff --git a/chrome/browser/net/chrome_url_request_context.cc b/chrome/browser/net/chrome_url_request_context.cc
index 732dc37..a40e548e 100644
--- a/chrome/browser/net/chrome_url_request_context.cc
+++ b/chrome/browser/net/chrome_url_request_context.cc
@@ -521,8 +521,9 @@ ChromeURLRequestContext* FactoryForMedia::Create() {
 ChromeURLRequestContextGetter::ChromeURLRequestContextGetter(
     Profile* profile,
     ChromeURLRequestContextFactory* factory)
-  : factory_(factory),
-    url_request_context_(NULL) {
+    : io_thread_(g_browser_process->io_thread()),
+      factory_(factory),
+      url_request_context_(NULL) {
   DCHECK(factory);
 
   // If a base profile was specified, listen for changes to the preferences.
@@ -540,6 +541,9 @@ ChromeURLRequestContextGetter::~ChromeURLRequestContextGetter() {
   DCHECK((factory_.get() && !url_request_context_.get()) ||
          (!factory_.get() && url_request_context_.get()));
 
+  if (url_request_context_)
+    io_thread_->UnregisterURLRequestContextGetter(this);
+
   // The scoped_refptr / scoped_ptr destructors take care of releasing
   // |factory_| and |url_request_context_| now.
 }
@@ -560,11 +564,17 @@ URLRequestContext* ChromeURLRequestContextGetter::GetURLRequestContext() {
     }
 
     factory_.reset();
+    io_thread_->RegisterURLRequestContextGetter(this);
   }
 
   return url_request_context_;
 }
 
+void ChromeURLRequestContextGetter::ReleaseURLRequestContext() {
+  DCHECK(url_request_context_);
+  url_request_context_ = NULL;
+}
+
 void ChromeURLRequestContextGetter::RegisterUserPrefs(
     PrefService* pref_service) {
   pref_service->RegisterBooleanPref(prefs::kNoProxyServer, false);
@@ -757,9 +767,12 @@ ChromeURLRequestContext::~ChromeURLRequestContext() {
 
 #if defined(USE_NSS)
   if (is_main()) {
-    DCHECK_EQ(this, net::GetURLRequestContextForOCSP());
-    // We are releasing the URLRequestContext used by OCSP handlers.
-    net::SetURLRequestContextForOCSP(NULL);
+    URLRequestContext* ocsp_context = net::GetURLRequestContextForOCSP();
+    if (ocsp_context) {
+      DCHECK_EQ(this, ocsp_context);
+      // We are releasing the URLRequestContext used by OCSP handlers.
+      net::SetURLRequestContextForOCSP(NULL);
+    }
   }
 #endif
 
diff --git a/chrome/browser/net/chrome_url_request_context.h b/chrome/browser/net/chrome_url_request_context.h
index 43b1b21..51d9246 100644
--- a/chrome/browser/net/chrome_url_request_context.h
+++ b/chrome/browser/net/chrome_url_request_context.h
@@ -242,6 +242,10 @@ class ChromeURLRequestContextGetter : public URLRequestContextGetter,
   virtual net::CookieStore* GetCookieStore();
   virtual scoped_refptr<base::MessageLoopProxy> GetIOMessageLoopProxy() const;
 
+  // Releases |url_request_context_|.  It's invalid to call
+  // GetURLRequestContext() after this point.
+  void ReleaseURLRequestContext();
+
   // Convenience overload of GetURLRequestContext() that returns a
   // ChromeURLRequestContext* rather than a URLRequestContext*.
   ChromeURLRequestContext* GetIOContext() {
@@ -309,6 +313,10 @@ class ChromeURLRequestContextGetter : public URLRequestContextGetter,
 
   PrefChangeRegistrar registrar_;
 
+  // |io_thread_| is always valid during the lifetime of |this| since |this| is
+  // deleted on the IO thread.
+  IOThread* const io_thread_;
+
   // Deferred logic for creating a ChromeURLRequestContext.
   // Access only from the IO thread.
   scoped_ptr<ChromeURLRequestContextFactory> factory_;