HttpServerProperties - Don't persist if SetSupportsSpdy is called with

the same origin (HostPortPair) and value (supports_spdy).

This change reduces the number of times SetSupportsSpdy tries to persist
HttpServerProperties to disk (currently ~5% of persist calls are due to
SetSupportsSpdy).

BUG=451256
R=rch@chromium.org

Review URL: https://codereview.chromium.org/1159853005

Cr-Commit-Position: refs/heads/master@{#333146}

net/http/http_server_properties.h

@@ -218,6 +218,9 @@ class NET_EXPORT HttpServerProperties {
   // request prioritization.
   virtual bool SupportsRequestPriority(const HostPortPair& server) = 0;
 
+  // Returns the value set by SetSupportsSpdy(). If not set, returns false.
+  virtual bool GetSupportsSpdy(const HostPortPair& server) = 0;
+
   // Add |server| into the persistent store. Should only be called from IO
   // thread.
   virtual void SetSupportsSpdy(const HostPortPair& server,

net/http/http_server_properties_impl.cc

@@ -157,9 +157,7 @@ bool HttpServerPropertiesImpl::SupportsRequestPriority(
   if (host_port_pair.host().empty())
     return false;
 
-  SpdyServerHostPortMap::iterator spdy_host_port =
-      spdy_servers_map_.Get(host_port_pair.ToString());
-  if (spdy_host_port != spdy_servers_map_.end() && spdy_host_port->second)
+  if (GetSupportsSpdy(host_port_pair))
     return true;
 
   const AlternativeService alternative_service =
@@ -167,6 +165,17 @@ bool HttpServerPropertiesImpl::SupportsRequestPriority(
   return alternative_service.protocol == QUIC;
 }
 
+bool HttpServerPropertiesImpl::GetSupportsSpdy(
+    const HostPortPair& host_port_pair) {
+  DCHECK(CalledOnValidThread());
+  if (host_port_pair.host().empty())
+    return false;
+
+  SpdyServerHostPortMap::iterator spdy_host_port =
+      spdy_servers_map_.Get(host_port_pair.ToString());
+  return spdy_host_port != spdy_servers_map_.end() && spdy_host_port->second;
+}
+
 void HttpServerPropertiesImpl::SetSupportsSpdy(
     const HostPortPair& host_port_pair,
     bool support_spdy) {

net/http/http_server_properties_impl.h

@@ -81,6 +81,7 @@ class NET_EXPORT HttpServerPropertiesImpl
   base::WeakPtr<HttpServerProperties> GetWeakPtr() override;
   void Clear() override;
   bool SupportsRequestPriority(const HostPortPair& server) override;
+  bool GetSupportsSpdy(const HostPortPair& server) override;
   void SetSupportsSpdy(const HostPortPair& server, bool support_spdy) override;
   bool RequiresHTTP11(const HostPortPair& server) override;
   void SetHTTP11Required(const HostPortPair& server) override;

net/http/http_server_properties_manager.cc

@@ -155,11 +155,19 @@ bool HttpServerPropertiesManager::SupportsRequestPriority(
   return http_server_properties_impl_->SupportsRequestPriority(server);
 }
 
+bool HttpServerPropertiesManager::GetSupportsSpdy(const HostPortPair& server) {
+  DCHECK(network_task_runner_->RunsTasksOnCurrentThread());
+  return http_server_properties_impl_->GetSupportsSpdy(server);
+}
+
 void HttpServerPropertiesManager::SetSupportsSpdy(const HostPortPair& server,
                                                   bool support_spdy) {
   DCHECK(network_task_runner_->RunsTasksOnCurrentThread());
 
+  bool old_support_spdy = http_server_properties_impl_->GetSupportsSpdy(server);
   http_server_properties_impl_->SetSupportsSpdy(server, support_spdy);
+  bool new_support_spdy = http_server_properties_impl_->GetSupportsSpdy(server);
+  if (old_support_spdy != new_support_spdy)
     ScheduleUpdatePrefsOnNetworkThread(SUPPORTS_SPDY);
 }
 

net/http/http_server_properties_manager.h

@@ -81,6 +81,7 @@ class NET_EXPORT HttpServerPropertiesManager : public HttpServerProperties {
   base::WeakPtr<HttpServerProperties> GetWeakPtr() override;
   void Clear() override;
   bool SupportsRequestPriority(const HostPortPair& server) override;
+  bool GetSupportsSpdy(const HostPortPair& server) override;
   void SetSupportsSpdy(const HostPortPair& server, bool support_spdy) override;
   bool RequiresHTTP11(const HostPortPair& server) override;
   void SetHTTP11Required(const HostPortPair& server) override;

net/http/http_server_properties_manager_unittest.cc

@@ -390,6 +390,8 @@ TEST_F(HttpServerPropertiesManagerTest, SupportsSpdy) {
   EXPECT_FALSE(
       http_server_props_manager_->SupportsRequestPriority(spdy_server_mail));
   http_server_props_manager_->SetSupportsSpdy(spdy_server_mail, true);
+  // ExpectScheduleUpdatePrefsOnNetworkThread() should be called only once.
+  http_server_props_manager_->SetSupportsSpdy(spdy_server_mail, true);
 
   // Run the task.
   base::RunLoop().RunUntilIdle();