Add pdfium::span::as_bytes() and as_writable_bytes().

Picks up some enhancements from base/span.h.  In turn, also adds
the size_bytes() helper.  Differs from base version in that it
works around C++14 enable_if_t<>, and avoids the dynamic_extent
template specialization tricks.

Use it in a few places where appropriate.

Change-Id: I86f72cf0023f2d4317a7afa351fddee601c8f86c
Reviewed-on: https://pdfium-review.googlesource.com/38251
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/core/fxcrt/bytestring_unittest.cpp b/core/fxcrt/bytestring_unittest.cpp
index fb5fc0d996..7095a1b799 100644
--- a/core/fxcrt/bytestring_unittest.cpp
+++ b/core/fxcrt/bytestring_unittest.cpp
@@ -1060,8 +1060,7 @@ TEST(ByteStringView, NotNull) {
   ByteStringView string3("abc");
   ByteStringView string6("abcdef");
   ByteStringView alternate_string3("abcdef", 3);
-  ByteStringView span_string4(
-      pdfium::span<const uint8_t>(reinterpret_cast<const uint8_t*>("abcd"), 4));
+  ByteStringView span_string4(pdfium::as_bytes(pdfium::make_span("abcd", 4)));
   ByteStringView embedded_nul_string7("abc\0def", 7);
   ByteStringView illegal_string7("abcdef", 7);
 
@@ -1355,8 +1354,8 @@ TEST(ByteStringView, OperatorEQ) {
   EXPECT_FALSE(c_string2 == byte_string_c);
   EXPECT_FALSE(c_string3 == byte_string_c);
 
-  pdfium::span<const uint8_t> span5(reinterpret_cast<const uint8_t*>("hello"),
-                                    5);
+  pdfium::span<const uint8_t> span5(
+      pdfium::as_bytes(pdfium::make_span("hello", 5)));
   EXPECT_EQ(byte_string_c.span(), span5);
 }