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, 7 insertions, 0 deletions

diff --git a/fpdfsdk/include/javascript/IJavaScript.h b/fpdfsdk/include/javascript/IJavaScript.h
index a05d4436e0..4db1bc6e27 100644
--- a/fpdfsdk/include/javascript/IJavaScript.h
+++ b/fpdfsdk/include/javascript/IJavaScript.h
@@ -7,6 +7,13 @@
 #ifndef _IJAVASCRIPT_H_
 #define _IJAVASCRIPT_H_
 
+#include "../../../core/include/fxcrt/fx_basic.h"
+
+class CPDF_Bookmark;
+class CPDF_FormField;
+class CPDFSDK_Annot;
+class CPDFSDK_Document;
+
 class IFXJS_Context
 {
 public: