Pass CJS_Runtime to JS callbacks.

This is much more convenient, since only a fraction of them
need an IJS_EventContext, which can be obtained from the
CJS_Runtime.

Make GetCurrentEventContext() specific to CJS_Runtime, and
return the concrete type.  This saves a lot of casting.

Change-Id: If79a3bcbf44de513f3caace153099234cc313d47
Reviewed-on: https://pdfium-review.googlesource.com/2793
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/javascript/console.cpp b/fpdfsdk/javascript/console.cpp
index 538a4ef..fdef98f 100644
--- a/fpdfsdk/javascript/console.cpp
+++ b/fpdfsdk/javascript/console.cpp
@@ -33,21 +33,21 @@
 
 console::~console() {}
 
-bool console::clear(IJS_EventContext* cc,
+bool console::clear(CJS_Runtime* pRuntime,
                     const std::vector<CJS_Value>& params,
                     CJS_Value& vRet,
                     CFX_WideString& sError) {
   return true;
 }
 
-bool console::hide(IJS_EventContext* cc,
+bool console::hide(CJS_Runtime* pRuntime,
                    const std::vector<CJS_Value>& params,
                    CJS_Value& vRet,
                    CFX_WideString& sError) {
   return true;
 }
 
-bool console::println(IJS_EventContext* cc,
+bool console::println(CJS_Runtime* pRuntime,
                       const std::vector<CJS_Value>& params,
                       CJS_Value& vRet,
                       CFX_WideString& sError) {
@@ -57,7 +57,7 @@
   return true;
 }
 
-bool console::show(IJS_EventContext* cc,
+bool console::show(CJS_Runtime* pRuntime,
                    const std::vector<CJS_Value>& params,
                    CJS_Value& vRet,
                    CFX_WideString& sError) {