Change print setting conventions for margins to support more options.

printing/print_job_constants.h

Index: printing/print_job_constants.h
diff --git a/printing/print_job_constants.h b/printing/print_job_constants.h
index cbdad74fb85283a4a643665d0725cf6468c76d0f..3ccb5acdbc51f4d2c049e9867fa3c1be8cb748d6 100644
--- a/printing/print_job_constants.h
+++ b/printing/print_job_constants.h
@@ -19,7 +19,6 @@ PRINTING_EXPORT extern const char kSettingColor[];
 PRINTING_EXPORT extern const char kSettingContentHeight[];
 PRINTING_EXPORT extern const char kSettingContentWidth[];
 PRINTING_EXPORT extern const char kSettingCopies[];
-PRINTING_EXPORT extern const char kSettingDefaultMarginsSelected[];
 PRINTING_EXPORT extern const char kSettingDeviceName[];
 PRINTING_EXPORT extern const char kSettingDuplexMode[];
 PRINTING_EXPORT extern const char kSettingGenerateDraftData[];
@@ -38,7 +37,8 @@ PRINTING_EXPORT extern const char kSettingMarginBottom[];
 PRINTING_EXPORT extern const char kSettingMarginLeft[];
 PRINTING_EXPORT extern const char kSettingMarginRight[];
 PRINTING_EXPORT extern const char kSettingMarginTop[];
-PRINTING_EXPORT extern const char kSettingMargins[];
+PRINTING_EXPORT extern const char kSettingMarginsCustom[];
+PRINTING_EXPORT extern const char kSettingMarginsType[];
 PRINTING_EXPORT extern const char kSettingPageRange[];
 PRINTING_EXPORT extern const char kSettingPageRangeFrom[];
 PRINTING_EXPORT extern const char kSettingPageRangeTo[];
@@ -76,6 +76,14 @@ enum ColorMode {
   CMYK,
 };
 
+// What kind of margins to use.
+enum MarginType {
+  DEFAULT_MARGINS,  // Default varies depending on headers being enabled or not
+  NO_MARGINS,
+  CUSTOM_MARGINS,
+  PRINTABLE_AREA_MARGINS,
+};
+
 }  // namespace printing
 
 #endif  // PRINTING_PRINT_JOB_CONSTANTS_H_