Make CFWL_Custom consistenly named.

It's part of the CFWL_*Imp hierarchy, and hence should be
named CFWL_CustomImp.  CFWL_Custom would belong to a differnt
hierarchy according to naming conventions.

R=ochang@chromium.org

Review URL: https://codereview.chromium.org/1491723002 .
diff --git a/xfa/src/fwl/src/core/fwl_widgetimp.cpp b/xfa/src/fwl/src/core/fwl_widgetimp.cpp
index 18a2301..4a8c0f8 100644
--- a/xfa/src/fwl/src/core/fwl_widgetimp.cpp
+++ b/xfa/src/fwl/src/core/fwl_widgetimp.cpp
@@ -1082,11 +1082,11 @@
   evt.m_pGraphics = pGraphics;

   return FWL_ERR_Succeeded;

 }

-class CFWL_Custom : public CFWL_WidgetImp {

+class CFWL_CustomImp : public CFWL_WidgetImp {

  public:

-  CFWL_Custom(IFWL_Widget* pOuter = NULL);

-  CFWL_Custom(const CFWL_WidgetImpProperties& properties,

-              IFWL_Widget* pOuter = NULL);

+  CFWL_CustomImp(IFWL_Widget* pOuter = NULL);

+  CFWL_CustomImp(const CFWL_WidgetImpProperties& properties,

+                 IFWL_Widget* pOuter = NULL);

   virtual FWL_ERR GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize = FALSE);

   virtual FWL_ERR Update();

   virtual FWL_ERR SetProxy(IFWL_Proxy* pProxy);

@@ -1094,25 +1094,25 @@
  protected:

   IFWL_Proxy* m_pProxy;

 };

-CFWL_Custom::CFWL_Custom(IFWL_Widget* pOuter)

+CFWL_CustomImp::CFWL_CustomImp(IFWL_Widget* pOuter)

     : CFWL_WidgetImp(pOuter), m_pProxy(NULL) {}

-CFWL_Custom::CFWL_Custom(const CFWL_WidgetImpProperties& properties,

-                         IFWL_Widget* pOuter)

+CFWL_CustomImp::CFWL_CustomImp(const CFWL_WidgetImpProperties& properties,

+                               IFWL_Widget* pOuter)

     : CFWL_WidgetImp(properties, pOuter), m_pProxy(NULL) {}

-FWL_ERR CFWL_Custom::GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize) {

+FWL_ERR CFWL_CustomImp::GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize) {

   if (m_pProxy &&

       (m_pProxy->GetWidgetRect(rect, bAutoSize) == FWL_ERR_Succeeded)) {

     return FWL_ERR_Succeeded;

   }

   return CFWL_WidgetImp::GetWidgetRect(rect, bAutoSize);

 }

-FWL_ERR CFWL_Custom::Update() {

+FWL_ERR CFWL_CustomImp::Update() {

   if (m_pProxy) {

     return m_pProxy->Update();

   }

   return CFWL_WidgetImp::Update();

 }

-FWL_ERR CFWL_Custom::SetProxy(IFWL_Proxy* pProxy) {

+FWL_ERR CFWL_CustomImp::SetProxy(IFWL_Proxy* pProxy) {

   m_pProxy = pProxy;

   return FWL_ERR_Succeeded;

 }

@@ -1123,13 +1123,13 @@
 }

 FWL_ERR IFWL_Custom::Initialize(const CFWL_WidgetImpProperties& properties,

                                 IFWL_Widget* pOuter) {

-  CFWL_Custom* pCustomImpl = new CFWL_Custom(properties, pOuter);

+  CFWL_CustomImp* pCustomImpl = new CFWL_CustomImp(properties, pOuter);

   SetImpl(pCustomImpl);

   pCustomImpl->SetInterface(this);

   return pCustomImpl->Initialize();

 }

 FWL_ERR IFWL_Custom::SetProxy(IFWL_Proxy* pProxy) {

-  return static_cast<CFWL_Custom*>(GetImpl())->SetProxy(pProxy);

+  return static_cast<CFWL_CustomImp*>(GetImpl())->SetProxy(pProxy);

 }

 void FWL_SetWidgetRect(IFWL_Widget* widget, const CFX_RectF& rect) {

   static_cast<CFWL_WidgetImp*>(widget->GetImpl())->m_pProperties->m_rtWidget =