Return error information from pdfium to JS.

This implements the previously unimplemented JS_Error() function.

Along the way:
- fix some IWYU when the include order in global.cpp was perturbed.
- remove some uses of JS_ErrorString, to increase transparency.
- use vp.IsSetting() in place of !vp.IsGetting() for clarity.
- specify an error string on several error return paths.
- add an error string for writing readonly properties.
- rename an error string constant to reflect the actual message.
- replace calls to variadic Format() with a function doing string appends.
- remove unused JS_GetClassName()

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/963193003

1 files changed, 16 insertions, 1 deletions

diff --git a/fpdfsdk/src/javascript/resource.cpp b/fpdfsdk/src/javascript/resource.cpp
index 1c453dcda7..be24ccd66c 100644
--- a/fpdfsdk/src/javascript/resource.cpp
+++ b/fpdfsdk/src/javascript/resource.cpp
@@ -39,9 +39,24 @@ CFX_WideString JSGetStringFromID(CJS_Context* pContext, FX_UINT id)
         return L"The second parameter can't be converted to a Date.";
     case IDS_STRING_JSPRINT2:
         return L"The second parameter is an invalid Date!";
-    case IDS_JSPARAM_INCORRECT:
+    case IDS_STRING_JSNOGLOBAL:
         return L"Global value not found.";
+    case IDS_STRING_JSREADONLY:
+        return L"Cannot assign to readonly property.";
     default:
         return L"";
     }
 }
+
+CFX_WideString JSFormatErrorString(const char* class_name,
+                                   const char* property_name,
+                                   const CFX_WideString& details) {
+    CFX_WideString result = CFX_WideString::FromLocal(class_name);
+    if (property_name) {
+        result += L".";
+        result += CFX_WideString::FromLocal(property_name);
+    }
+    result += L": ";
+    result += details;
+    return result;
+}