Revert of Do not consolidate data in BMPImageDecoder

Source/platform/image-decoders/FastSharedBufferReader.h

Index: Source/platform/image-decoders/FastSharedBufferReader.h
diff --git a/Source/platform/image-decoders/FastSharedBufferReader.h b/Source/platform/image-decoders/FastSharedBufferReader.h
index 5d0d11b3ca2422d759a337e9146df52071492c10..cbff91a330cbe44fb8809866016b88dfd3c5979e 100644
--- a/Source/platform/image-decoders/FastSharedBufferReader.h
+++ b/Source/platform/image-decoders/FastSharedBufferReader.h
@@ -46,8 +46,6 @@ class PLATFORM_EXPORT FastSharedBufferReader {
 public:
     FastSharedBufferReader(PassRefPtr<SharedBuffer> data);
 
-    void setData(PassRefPtr<SharedBuffer>);
-
     // Returns a consecutive buffer that carries the data starting
     // at |dataPosition| with |length| bytes.
     // This method returns a pointer to a memory segment stored in