Support wbmp that are supported by SkImageDecoder

tests/CodexTest.cpp

Index: tests/CodexTest.cpp
diff --git a/tests/CodexTest.cpp b/tests/CodexTest.cpp
index b53cbe1a4d7dd6c468af08f678f4b27087e91be6..697ba749f70861d9678a19894622dff8ec1ed8bf 100644
--- a/tests/CodexTest.cpp
+++ b/tests/CodexTest.cpp
@@ -10,9 +10,11 @@
 #include "SkBitmap.h"
 #include "SkCodec.h"
 #include "SkData.h"
+#include "SkImageDecoder.h"
 #include "SkMD5.h"
 #include "SkRandom.h"
 #include "SkStream.h"
+#include "SkStreamPriv.h"
 #include "SkPngChunkReader.h"
 #include "Test.h"
 
@@ -845,3 +847,33 @@ DEF_TEST(Codec_pngChunkReader, r) {
     REPORTER_ASSERT(r, chunkReader.allHaveBeenSeen());
 }
 #endif // PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+
+// SkCodec's wbmp decoder was initially more restrictive than SkImageDecoder.
+// It required the second byte to be zero. But SkImageDecoder allowed a couple
+// of bits to be 1 (so long as they do not overlap with 0x9F). Test that
+// SkCodec now supports an image with these bits set.
+DEF_TEST(Codec_wbmp, r) {
+    const char* path = "mandrill.wbmp";

[msarett, 2015/11/30 13:24:55]

Did we fail on this image before you made this change?

[scroggo, 2015/11/30 13:48:13]

No. See below - I had to modify the image to make it fail. With the code change,
the modified image succeeds.

Let me know if I should add comments to clarify this.

[msarett, 2015/11/30 14:00:44]

My mistake, it's perfectly clear.

+    SkAutoTDelete<SkStream> stream(resource(path));
+    if (!stream) {
+        SkDebugf("Missing resource '%s'\n", path);
+        return;
+    }
+
+    // Modify the stream to contain a second byte with some bits set.
+    SkAutoTUnref<SkData> data(SkCopyStreamToData(stream));
+    uint8_t* writeableData = static_cast<uint8_t*>(data->writable_data());
+    writeableData[1] = static_cast<uint8_t>(~0x9F);
+
+    // SkImageDecoder supports this.
+    SkBitmap bitmap;
+    REPORTER_ASSERT(r, SkImageDecoder::DecodeMemory(data->data(), data->size(), &bitmap));
+
+    // So SkCodec should, too.
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(data));
+    REPORTER_ASSERT(r, codec);
+    if (!codec) {
+        return;
+    }
+    test_info(r, codec, codec->getInfo(), SkCodec::kSuccess, nullptr);
+}