Rendering: Adds PDF support behind feature toggle (#81811)

* start pdf refactor

* Update AppChrome.tsx

* Update AppChrome.tsx

* add encoding param to rendering grpc service

* fix plugin mode

* clean up

* fix backend tests

* fix lint errors

* Support pdf encoding in render http api

---------

Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

pkg/services/rendering/http_mode.go

@@ -14,6 +14,8 @@ import (
 	"os"
 	"strconv"
 	"time"
+
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 )
 
 var netTransport = &http.Transport{
@@ -36,8 +38,16 @@ var (
 	remoteVersionRefreshInterval               = time.Minute * 15
 )
 
-func (rs *RenderingService) renderViaHTTP(ctx context.Context, renderKey string, opts Opts) (*RenderResult, error) {
-	filePath, err := rs.getNewFilePath(RenderPNG)
+func (rs *RenderingService) renderViaHTTP(ctx context.Context, renderType RenderType, renderKey string, opts Opts) (*RenderResult, error) {
+	if renderType == RenderPDF {
+		if !rs.features.IsEnabled(ctx, featuremgmt.FlagNewPDFRendering) {
+			return nil, fmt.Errorf("feature 'newPDFRendering' disabled")
+		}
+
+		opts.Encoding = "pdf"
+	}
+
+	filePath, err := rs.getNewFilePath(renderType)
 	if err != nil {
 		return nil, err
 	}