Update callers of httputils.ReportError to specify message

ct/go/ctfe/chromium_perf/chromium_perf.go

 /*
         Handlers and types specific to Chromium perf tasks.
 */
 
 package chromium_perf
 
 import (
         "database/sql"
         "encoding/json"
         "fmt"
@@ skipping 216 matching lines @@
         default:
                 return nil, fmt.Errorf("CL project is %s; only chromium and skia are supported.", detail.Project)
         }
         return clData, nil
 }
 
 func getCLHandler(w http.ResponseWriter, r *http.Request) {
         w.Header().Set("Content-Type", "application/json")
         detail, err := getCLDetail(r.FormValue("cl"))
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get CL details")
                 return
         }
         if detail.Issue == 0 {
                 // Return successful empty response, since the user could still be typing.
                 if err := json.NewEncoder(w).Encode(map[string]interface{}{}); err != nil {
                         httputils.ReportError(w, r, err, "Failed to encode JSON")
                 }
                 return
         }
         patch, err := getCLPatch(detail, 0)
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get CL patch")
                 return
         }
         clData, err := gatherCLData(detail, patch)
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get CL data")
                 return
         }
         if err = json.NewEncoder(w).Encode(clData); err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to encode JSON")
                 return
         }
 }
 
 type AddTaskVars struct {
         task_common.AddTaskCommonVars
 
         Benchmark            string `json:"benchmark"`
         Platform             string `json:"platform"`
         PageSets             string `json:"page_sets"`
@@ skipping 127 matching lines @@
         trybotTask := TrybotTask{}
         if err := json.Unmarshal(data, &trybotTask); err != nil {
                 httputils.ReportError(w, r, err, fmt.Sprintf("Failed to add %v trybot task", trybotTask))
                 return
         }
 
         task := &trybotTask.TaskVars
         // Add patch data to the task.
         detail, err := getCLDetail(trybotTask.Issue)
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get CL details")
                 return
         }
         patchsetID, err := strconv.Atoi(trybotTask.PatchsetID)
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get Patchset ID")
                 return
         }
         patch, err := getCLPatch(detail, patchsetID)
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get CL patch")
                 return
         }
         clData, err := gatherCLData(detail, patch)
         if err != nil {
-                httputils.ReportError(w, r, err, "")
+                httputils.ReportError(w, r, err, "Failed to get CL data")
                 return
         }
 
         task.Description = fmt.Sprintf("Trybot run for http://codereview.chromium.org/%s#ps%s", clData["cl"], clData["patchset"])
         if val, ok := clData["chromium_patch"]; ok {
                 task.ChromiumPatch = val
         }
         if val, ok := clData["skia_patch"]; ok {
                 task.SkiaPatch = val
         }
@@ skipping 43 matching lines @@
         r.HandleFunc("/"+ctfeutil.GET_CHROMIUM_PERF_RUN_STATUS_URI, getTaskStatusHandler).Methods("GET")
         r.HandleFunc("/"+ctfeutil.CHROMIUM_PERF_PARAMETERS_POST_URI, parametersHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.CHROMIUM_PERF_CL_DATA_POST_URI, getCLHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.ADD_CHROMIUM_PERF_TASK_POST_URI, addTaskHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.GET_CHROMIUM_PERF_TASKS_POST_URI, getTasksHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.UPDATE_CHROMIUM_PERF_TASK_POST_URI, updateTaskHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.WEBHOOK_ADD_CHROMIUM_PERF_TASK_POST_URI, addTrybotTaskHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.DELETE_CHROMIUM_PERF_TASK_POST_URI, deleteTaskHandler).Methods("POST")
         r.HandleFunc("/"+ctfeutil.REDO_CHROMIUM_PERF_TASK_POST_URI, redoTaskHandler).Methods("POST")
 }