Add experimental code behind a flag for Content Size Policy

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index 981c71ba454f337c573f6c9b64805d7934a13ce5..7fa16021fdebcc3bcbb9bd4ed81000c2a81e2c2a 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -47,6 +47,7 @@
 #include "content/browser/frame_host/navigator.h"
 #include "content/browser/loader/async_resource_handler.h"
 #include "content/browser/loader/async_revalidation_manager.h"
+#include "content/browser/loader/content_size_resource_handler_manager.h"
 #include "content/browser/loader/cross_site_resource_handler.h"
 #include "content/browser/loader/detachable_resource_handler.h"
 #include "content/browser/loader/loader_delegate.h"
@@ -1070,6 +1071,10 @@ std::unique_ptr<net::ClientCertStore>
 
 void ResourceDispatcherHostImpl::OnInit() {
   scheduler_.reset(new ResourceScheduler);
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kContentSizePolicy)) {
+    content_size_manager_.reset(new ContentSizeResourceHandlerManager());
+  }
 }
 
 void ResourceDispatcherHostImpl::OnShutdown() {
@@ -1099,6 +1104,7 @@ void ResourceDispatcherHostImpl::OnShutdown() {
   }
 
   scheduler_.reset();
+  content_size_manager_.reset();
 }
 
 bool ResourceDispatcherHostImpl::OnMessageReceived(
@@ -1679,6 +1685,14 @@ ResourceDispatcherHostImpl::AddStandardHandlers(
         BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE)));
   }
 
+  // Insert a handler for inspecting content sizes as they come in. Note that
+  // this handler can cancel requests if they are associated with frames that go
+  // over a prescribed limit.
+  if (content_size_manager_) {
+    handler =
+        content_size_manager_->MaybeAddHandler(std::move(handler), request);
+  }
+
   // TODO(ricea): Stop looking this up so much.
   ResourceRequestInfoImpl* info = ResourceRequestInfoImpl::ForRequest(request);
   throttles.push_back(scheduler_->ScheduleRequest(child_id, route_id,
@@ -2279,6 +2293,8 @@ void ResourceDispatcherHostImpl::SetLoaderDelegate(
 void ResourceDispatcherHostImpl::OnRenderFrameDeleted(
     const GlobalFrameRoutingId& global_routing_id) {
   CancelRequestsForRoute(global_routing_id);
+  if (content_size_manager_)
+    content_size_manager_->FrameDeleted(global_routing_id);
 }
 
 // static