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, 5 insertions, 0 deletions

diff --git a/fpdfsdk/include/javascript/JS_Object.h b/fpdfsdk/include/javascript/JS_Object.h
index dbf7da68a4..86ae14f3d0 100644
--- a/fpdfsdk/include/javascript/JS_Object.h
+++ b/fpdfsdk/include/javascript/JS_Object.h
@@ -7,6 +7,11 @@
 #ifndef _JS_OBJECT_H_
 #define _JS_OBJECT_H_
 
+#include "../fsdk_define.h"  // For FX_UINT
+#include "../fsdk_mgr.h"  // For CPDFDoc_Environment
+#include "../fx_systemhandler.h"  // For IFX_SystemHandler
+
+class CPDFSDK_PageView;
 class CJS_Object;
 class CJS_Timer;
 class CJS_Context;