Chromecast startup race: don't add filter before HostResolver exists.

HostResolver is on the I/O thread, which doesn't always have a chance
to run before filters are added. Get HostResolver from the I/O thread.

R=lcwu@chromium.org,byungchul@chromium.org
BUG=None, but the internal builders are failing

Review URL: https://codereview.chromium.org/1081673004

Cr-Commit-Position: refs/heads/master@{#326092}

2 files changed, 33 insertions, 4 deletions

diff --git a/chromecast/browser/cast_content_browser_client.cc b/chromecast/browser/cast_content_browser_client.cc
index 3234a59..beae0d3 100644
--- a/chromecast/browser/cast_content_browser_client.cc
+++ b/chromecast/browser/cast_content_browser_client.cc
@@ -40,6 +40,7 @@
 #include "content/public/common/web_preferences.h"
 #include "gin/v8_initializer.h"
 #include "net/ssl/ssl_cert_request_info.h"
+#include "net/url_request/url_request_context_getter.h"
 #include "ui/gl/gl_switches.h"
 
 #if defined(OS_ANDROID)
@@ -74,22 +75,43 @@ content::BrowserMainParts* CastContentBrowserClient::CreateBrowserMainParts(
 
 void CastContentBrowserClient::RenderProcessWillLaunch(
     content::RenderProcessHost* host) {
-  scoped_refptr<content::BrowserMessageFilter> network_hints_message_filter(
-      new network_hints::NetworkHintsMessageFilter(
-          url_request_context_factory_->host_resolver()));
-  host->AddFilter(network_hints_message_filter.get());
 #if !defined(OS_ANDROID)
   scoped_refptr<media::CmaMessageFilterHost> cma_message_filter(
       new media::CmaMessageFilterHost(host->GetID()));
   host->AddFilter(cma_message_filter.get());
 #endif  // !defined(OS_ANDROID)
 
+  // Forcibly trigger I/O-thread URLRequestContext initialization before
+  // getting HostResolver.
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&net::URLRequestContextGetter::GetURLRequestContext,
+                 base::Unretained(
+                    url_request_context_factory_->GetSystemGetter())),
+      base::Bind(&CastContentBrowserClient::AddNetworkHintsMessageFilter,
+                 base::Unretained(this), host->GetID()));
+
   auto extra_filters = PlatformGetBrowserMessageFilters();
   for (auto const& filter : extra_filters) {
     host->AddFilter(filter.get());
   }
 }
 
+void CastContentBrowserClient::AddNetworkHintsMessageFilter(
+    int render_process_id, net::URLRequestContext* context) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  content::RenderProcessHost* host =
+      content::RenderProcessHost::FromID(render_process_id);
+  if (!host)
+    return;
+
+  scoped_refptr<content::BrowserMessageFilter> network_hints_message_filter(
+      new network_hints::NetworkHintsMessageFilter(
+          url_request_context_factory_->host_resolver()));
+  host->AddFilter(network_hints_message_filter.get());
+}
+
 net::URLRequestContextGetter* CastContentBrowserClient::CreateRequestContext(
     content::BrowserContext* browser_context,
     content::ProtocolHandlerMap* protocol_handlers,
diff --git a/chromecast/browser/cast_content_browser_client.h b/chromecast/browser/cast_content_browser_client.h
index c35bc2e..193a090 100644
--- a/chromecast/browser/cast_content_browser_client.h
+++ b/chromecast/browser/cast_content_browser_client.h
@@ -19,6 +19,10 @@ namespace content {
 class BrowserMessageFilter;
 }
 
+namespace net {
+class HostResolver;
+}
+
 namespace chromecast {
 namespace shell {
 
@@ -99,6 +103,9 @@ class CastContentBrowserClient: public content::ContentBrowserClient {
 #endif  // defined(OS_ANDROID) && defined(VIDEO_HOLE)
 
  private:
+  void AddNetworkHintsMessageFilter(int render_process_id,
+                                    net::URLRequestContext* context);
+
   net::X509Certificate* SelectClientCertificateOnIOThread(
       GURL requesting_url,
       int render_process_id);