Remove unused codepage from WideString::GetWideString().

Consolidate code into sole caller, which always retrieves a string
from the "default ANSI code page". Add unit test for this code path.
Fix sign extension bug giving bogus 0xffffff80 codepoint uncovered
by unit test on non-windows. Note windows result is different because
the system conversion routine does actually work.

Change-Id: I1c1246b203ee66e9ff0b6fccf97594788bcd0fca
Reviewed-on: https://pdfium-review.googlesource.com/39730
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/core/fxcrt/widestring_unittest.cpp b/core/fxcrt/widestring_unittest.cpp
index 9d38aa45e9..160dc929db 100644
--- a/core/fxcrt/widestring_unittest.cpp
+++ b/core/fxcrt/widestring_unittest.cpp
@@ -1025,6 +1025,27 @@ TEST(WideString, ToDefANSI) {
                          .ToDefANSI());
 }
 
+TEST(WideString, FromLocal) {
+  EXPECT_EQ(L"", WideString::FromLocal(ByteStringView()));
+#if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_
+  const wchar_t* kResult =
+      L"x"
+      L"\u20ac"
+      L"\u00ff"
+      L"y";
+#else
+  const wchar_t* kResult =
+      L"x"
+      L"\u0080"
+      L"\u00ff"
+      L"y";
+#endif
+  EXPECT_EQ(kResult, WideString::FromLocal("x"
+                                           "\x80"
+                                           "\xff"
+                                           "y"));
+}
+
 TEST(WideStringView, FromVector) {
   std::vector<WideStringView::UnsignedType> null_vec;
   WideStringView null_string(null_vec);