Printing: Catch more error conditions and remove more cruft.

chrome/browser/ui/webui/print_preview/print_preview_handler.cc

Index: chrome/browser/ui/webui/print_preview/print_preview_handler.cc
===================================================================
--- chrome/browser/ui/webui/print_preview/print_preview_handler.cc	(revision 126455)
+++ chrome/browser/ui/webui/print_preview/print_preview_handler.cc	(working copy)
@@ -120,29 +120,15 @@
 
 
 // Get the print job settings dictionary from |args|. The caller takes
-// ownership of the returned DictionaryValue. Returns NULL on failure.
+// ownership of the returned DictionaryValue.
 DictionaryValue* GetSettingsDictionary(const ListValue* args) {
   std::string json_str;
-  if (!args->GetString(0, &json_str)) {
-    NOTREACHED() << "Could not read JSON argument";
-    return NULL;
-  }
-  if (json_str.empty()) {
-    NOTREACHED() << "Empty print job settings";
-    return NULL;
-  }
+  CHECK(args->GetString(0, &json_str));

[Lei Zhang, 2012/03/14 05:40:05]

Unless the user is messing with the print preview JS / DOM through the
inspector, we should never hit these checks.

+  CHECK(!json_str.empty());
   scoped_ptr<DictionaryValue> settings(static_cast<DictionaryValue*>(
       base::JSONReader::Read(json_str, false)));
-  if (!settings.get() || !settings->IsType(Value::TYPE_DICTIONARY)) {
-    NOTREACHED() << "Print job settings must be a dictionary.";
-    return NULL;
-  }
-
-  if (settings->empty()) {
-    NOTREACHED() << "Print job settings dictionary is empty";
-    return NULL;
-  }
-
+  CHECK(settings.get() && settings->IsType(Value::TYPE_DICTIONARY));
+  CHECK(!settings->empty());
   return settings.release();
 }
 
@@ -283,10 +269,8 @@
 }
 
 void PrintPreviewHandler::HandleGetPreview(const ListValue* args) {
-  DCHECK_EQ(3U, args->GetSize());
+  CHECK_EQ(3U, args->GetSize());
   scoped_ptr<DictionaryValue> settings(GetSettingsDictionary(args));
-  if (!settings.get())
-    return;
   int request_id = -1;
   if (!settings->GetInteger(printing::kPreviewRequestID, &request_id))
     return;
@@ -313,10 +297,8 @@
   // Retrieve the page title and url and send it to the renderer process if
   // headers and footers are to be displayed.
   bool display_header_footer = false;
-  if (!settings->GetBoolean(printing::kSettingHeaderFooterEnabled,
-                            &display_header_footer)) {
-    NOTREACHED();
-  }
+  CHECK(settings->GetBoolean(printing::kSettingHeaderFooterEnabled,
+                             &display_header_footer));
   if (display_header_footer) {
     settings->SetString(printing::kSettingHeaderFooterTitle,
                         initiator_tab->web_contents()->GetTitle());
@@ -329,19 +311,16 @@
   }
 
   bool generate_draft_data = false;
-  bool success = settings->GetBoolean(printing::kSettingGenerateDraftData,
-                                      &generate_draft_data);
-  DCHECK(success);
+  CHECK(settings->GetBoolean(printing::kSettingGenerateDraftData,
+                             &generate_draft_data));
 
   if (!generate_draft_data) {
     double draft_page_count_double = -1;
-    success = args->GetDouble(1, &draft_page_count_double);
-    DCHECK(success);
+    CHECK(args->GetDouble(1, &draft_page_count_double));
     int draft_page_count = static_cast<int>(draft_page_count_double);
 
     bool preview_modifiable = false;
-    success = args->GetBoolean(2, &preview_modifiable);
-    DCHECK(success);
+    CHECK(args->GetBoolean(2, &preview_modifiable));
 
     if (draft_page_count != -1 && preview_modifiable &&
         print_preview_ui->GetAvailableDraftPageCount() != draft_page_count) {
@@ -355,6 +334,8 @@
 }
 
 void PrintPreviewHandler::HandlePrint(const ListValue* args) {
+  CHECK_EQ(2U, args->GetSize());
+
   ReportStats();
 
   // Record the number of times the user requests to regenerate preview data
@@ -369,8 +350,6 @@
   }
 
   scoped_ptr<DictionaryValue> settings(GetSettingsDictionary(args));
-  if (!settings.get())
-    return;
 
   // Storing last used settings.
   GetStickySettings()->Store(*settings);
@@ -395,8 +374,7 @@
 
   if (is_cloud_printer) {
     std::string print_ticket;
-    bool res = args->GetString(1, &print_ticket);
-    DCHECK(res);
+    CHECK(args->GetString(1, &print_ticket));
     SendCloudPrintJob(*settings, print_ticket);
   } else if (print_to_pdf) {
     HandlePrintToPdf(*settings);
@@ -491,6 +469,7 @@
 }
 
 void PrintPreviewHandler::HandleSaveLastPrinter(const ListValue* args) {
+  CHECK_EQ(2U, args->GetSize());
   std::string data_to_save;
   if (args->GetString(0, &data_to_save) && !data_to_save.empty())
     GetStickySettings()->StorePrinterName(data_to_save);
@@ -500,10 +479,10 @@
 }
 
 void PrintPreviewHandler::HandleGetPrinterCapabilities(const ListValue* args) {
+  CHECK_EQ(1U, args->GetSize());
   std::string printer_name;
-  bool ret = args->GetString(0, &printer_name);
-  if (!ret || printer_name.empty())
-    return;
+  CHECK(args->GetString(0, &printer_name));
+  CHECK(!printer_name.empty());
 
   scoped_refptr<PrintSystemTaskProxy> task =
       new PrintSystemTaskProxy(AsWeakPtr(),