Reduce/remove usage of BrowserThread in content/browser/loader.

content/browser/loader/resource_loader.cc

Index: content/browser/loader/resource_loader.cc
diff --git a/content/browser/loader/resource_loader.cc b/content/browser/loader/resource_loader.cc
index eafe82997771ac9c798d9e5676f69aaae2ce273d..c65a46588a4cdc9d3e9515592745b1e45354373b 100644
--- a/content/browser/loader/resource_loader.cc
+++ b/content/browser/loader/resource_loader.cc
@@ -17,6 +17,7 @@
 #include "content/browser/appcache/appcache_interceptor.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/loader/detachable_resource_handler.h"
+#include "content/browser/loader/loader_globals.h"
 #include "content/browser/loader/resource_controller.h"
 #include "content/browser/loader/resource_handler.h"
 #include "content/browser/loader/resource_loader_delegate.h"
@@ -446,7 +447,8 @@ void ResourceLoader::OnReadCompleted(net::URLRequest* unused, int bytes_read) {
 
 void ResourceLoader::CancelSSLRequest(int error,

[jam, 2017/03/29 15:44:32]

ResourceLoader is created from RDH, so we know it's created on the right thread.
so it should have a base::ThreadChecker member and it can use it in these
methods

[ananta, 2017/03/29 19:41:04]

Done.

                                       const net::SSLInfo* ssl_info) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(
+      LoaderGlobals::Get()->io_thread_task_runner()->BelongsToCurrentThread());
 
   // The request can be NULL if it was cancelled by the renderer (as the
   // request of the user navigating to a new page from the location bar).
@@ -462,7 +464,8 @@ void ResourceLoader::CancelSSLRequest(int error,
 }
 
 void ResourceLoader::ContinueSSLRequest() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(
+      LoaderGlobals::Get()->io_thread_task_runner()->BelongsToCurrentThread());
 
   DVLOG(1) << "ContinueSSLRequest() url: " << request_->url().spec();