output/httpd: move queue size check to HttpdClient::PushPage()

Don't let the server care for client problems.

src/output/HttpdClient.cxx

@@ -387,6 +387,12 @@ HttpdClient::PushPage(Page *page)
 		/* the client is still writing the HTTP request */
 		return;
 
+	if (queue_size > 256 * 1024) {
+		FormatDebug(httpd_output_domain,
+			    "client is too slow, flushing its queue");
+		ClearQueue();
+	}
+
 	page->Ref();
 	pages.push(page);
 	queue_size += page->size;

src/output/HttpdClient.hxx

@@ -142,14 +142,6 @@ public:
 
 	void LockClose();
 
-	/**
-	 * Returns the total size of this client's page queue.
-	 */
-	gcc_pure
-	size_t GetQueueSize() const {
-		return queue_size;
-	}
-
 	/**
 	 * Clears the page queue.
 	 */

src/output/HttpdOutputPlugin.cxx

@@ -401,16 +401,6 @@ HttpdOutput::BroadcastPage(Page *page)
 void
 HttpdOutput::BroadcastFromEncoder()
 {
-	mutex.lock();
-	for (auto &client : clients) {
-		if (client.GetQueueSize() > 256 * 1024) {
-			FormatDebug(httpd_output_domain,
-				    "client is too slow, flushing its queue");
-			client.CancelQueue();
-		}
-	}
-	mutex.unlock();
-
 	Page *page;
 	while ((page = ReadPage()) != nullptr) {
 		BroadcastPage(page);