Convert string class names

Automated using git grep & sed.
Replace StringC classes with StringView classes.
Remove the CFX_ prefix and put string classes in fxcrt namespace.
Change AsStringC() to AsStringView().
Rename tests from TEST(fxcrt, *String*Foo) to TEST(*String*,
Foo).
Couple of tests needed to have their names regularlized.

BUG=pdfium:894

Change-Id: I7ca038685c8d803795f3ed02545124f7a224c83d
Reviewed-on: https://pdfium-review.googlesource.com/14151
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
diff --git a/xfa/fxfa/cxfa_ffpageview.h b/xfa/fxfa/cxfa_ffpageview.h
index f2451fb..4e79ad5 100644
--- a/xfa/fxfa/cxfa_ffpageview.h
+++ b/xfa/fxfa/cxfa_ffpageview.h
@@ -92,7 +92,7 @@
 
  protected:
   CXFA_FFWidget* GetTraverseWidget(CXFA_FFWidget* pWidget);
-  CXFA_FFWidget* FindWidgetByName(const CFX_WideString& wsWidgetName,
+  CXFA_FFWidget* FindWidgetByName(const WideString& wsWidgetName,
                                   CXFA_FFWidget* pRefWidget);
   void CreateTabOrderWidgetArray();
   void CreateSpaceOrderWidgetArray(std::vector<CXFA_FFWidget*>* WidgetArray);