Revert of skstd -> std for unique_ptr (patchset #17 id:320001 of https://codereview.chromium.org/1436033003/ )

Reason for revert:
Chromium bots can't handle forward declared types, e.g.

struct Foo {
   int x,y;
   std::unique_ptr<Foo> next;
};

https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_asan_rel_ng/builds/86497

Original issue's description:
> skstd -> std for unique_ptr
>
> TBR=reed@google.com
> No public API changes.
>
> BUG=skia:4564
>
> Committed: https://skia.googlesource.com/skia/+/755c553c17b82bb5de3d9cc8d3b2a866ff9e9e50
>
> CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Mac10.9-Clang-x86_64-Release-CMake-Trybot,Build-Ubuntu-GCC-x86_64-Debug-CrOS_Link-Trybot;client.skia:Perf-Mac10.9-Clang-MacMini6.2-CPU-AVX-x86_64-Release-Trybot,Test-iOS-Clang-iPad4-GPU-SGX554-Arm7-Release-Trybot
>
> Committed: https://skia.googlesource.com/skia/+/06189155d987db5c7e69015f6ea87c2168d6a065
>
> Committed: https://skia.googlesource.com/skia/+/70e8dfca4a7f5bce97b8021a6e378c4828b09c8c
>
> Committed: https://skia.googlesource.com/skia/+/dadfc245cc9a0279ff7b73da3344f2ca5d139907

TBR=bungeman@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4564

Review URL: https://codereview.chromium.org/1498583002

1 files changed, 1 insertions, 1 deletions

diff --git a/src/android/SkBitmapRegionDecoder.cpp b/src/android/SkBitmapRegionDecoder.cpp
index f11bf40d74..a153282b09 100644
--- a/src/android/SkBitmapRegionDecoder.cpp
+++ b/src/android/SkBitmapRegionDecoder.cpp
@@ -54,7 +54,7 @@ SkBitmapRegionDecoder* SkBitmapRegionDecoder::Create(
                     SkAndroidCodec::NewFromStream(streamDeleter.detach());
             if (nullptr == codec) {
                 SkCodecPrintf("Error: Failed to create codec.\n");
-                return nullptr;
+                return NULL;
             }
 
             SkEncodedFormat format = codec->getEncodedFormat();