Moving GraphicsContext and dependencies from core to platform.

Source/platform/image-decoders/webp/WEBPImageDecoder.h

Index: Source/platform/image-decoders/webp/WEBPImageDecoder.h
diff --git a/Source/core/platform/image-decoders/webp/WEBPImageDecoder.h b/Source/platform/image-decoders/webp/WEBPImageDecoder.h
similarity index 96%
rename from Source/core/platform/image-decoders/webp/WEBPImageDecoder.h
rename to Source/platform/image-decoders/webp/WEBPImageDecoder.h
index 2a165cd0329397f83ff0523fd2b615b03c119453..778768b3d0f8ca8dab723755bd41a93a1fa448c0 100644
--- a/Source/core/platform/image-decoders/webp/WEBPImageDecoder.h
+++ b/Source/platform/image-decoders/webp/WEBPImageDecoder.h
@@ -29,14 +29,14 @@
 #ifndef WEBPImageDecoder_h
 #define WEBPImageDecoder_h
 
-#include "core/platform/image-decoders/ImageDecoder.h"
+#include "platform/image-decoders/ImageDecoder.h"
 
 #include "webp/decode.h"
 #include "webp/demux.h"
 
 namespace WebCore {
 
-class WEBPImageDecoder : public ImageDecoder {
+class PLATFORM_EXPORT WEBPImageDecoder : public ImageDecoder {
 public:
     WEBPImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption, size_t maxDecodedBytes);
     virtual ~WEBPImageDecoder();