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/core/fpdfapi/render/cpdf_type3cache.h b/core/fpdfapi/render/cpdf_type3cache.h
index 36a1d6f..ab748ba 100644
--- a/core/fpdfapi/render/cpdf_type3cache.h
+++ b/core/fpdfapi/render/cpdf_type3cache.h
@@ -39,7 +39,7 @@
                                                float retinaScaleY);
 
   CFX_UnownedPtr<CPDF_Type3Font> const m_pFont;
-  std::map<CFX_ByteString, std::unique_ptr<CPDF_Type3Glyphs>> m_SizeMap;
+  std::map<ByteString, std::unique_ptr<CPDF_Type3Glyphs>> m_SizeMap;
 };
 
 #endif  // CORE_FPDFAPI_RENDER_CPDF_TYPE3CACHE_H_