Updates to skimage tool to use it for testing.

src/images/SkImageDecoder_wbmp.cpp

Index: src/images/SkImageDecoder_wbmp.cpp
diff --git a/src/images/SkImageDecoder_wbmp.cpp b/src/images/SkImageDecoder_wbmp.cpp
index 96677ccafc50f34f4e5c1e22b18fec5161f5afc5..0cce60ed6e2845442cc3d46311d4770fd57a0257 100644
--- a/src/images/SkImageDecoder_wbmp.cpp
+++ b/src/images/SkImageDecoder_wbmp.cpp
@@ -21,6 +21,8 @@ public:
         return kWBMP_Format;
     }
 
+    virtual Format onGetFormat(SkStream*) const SK_OVERRIDE;
+
 protected:
     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE;
 
@@ -155,6 +157,14 @@ bool SkWBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* decodedBitmap,
     return true;
 }
 
+SkImageDecoder::Format SkWBMPImageDecoder::onGetFormat(SkStream* stream) const {
+    wbmp_head head;
+    if (head.init(stream)) {
+        return kWBMP_Format;
+    }
+    return kUnknown_Format;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 DEFINE_DECODER_CREATOR(WBMPImageDecoder);
 ///////////////////////////////////////////////////////////////////////////////