Moving GraphicsContext and dependencies from core to platform.

Source/platform/graphics/ImageDecodingStore.h

Index: Source/platform/graphics/ImageDecodingStore.h
diff --git a/Source/core/platform/graphics/ImageDecodingStore.h b/Source/platform/graphics/ImageDecodingStore.h
similarity index 98%
rename from Source/core/platform/graphics/ImageDecodingStore.h
rename to Source/platform/graphics/ImageDecodingStore.h
index 77c24858ed3372dfe400874cacc5bb115a632f88..9f54d04f2b8cd336ccc11d6cba54a6af1043116f 100644
--- a/Source/core/platform/graphics/ImageDecodingStore.h
+++ b/Source/platform/graphics/ImageDecodingStore.h
@@ -28,10 +28,11 @@
 
 #include "SkSize.h"
 #include "SkTypes.h"
-#include "core/platform/graphics/DiscardablePixelRef.h"
-#include "core/platform/image-decoders/ImageDecoder.h"
+#include "platform/PlatformExport.h"
+#include "platform/graphics/DiscardablePixelRef.h"
 #include "platform/graphics/ScaledImageFragment.h"
-#include "platform/graphics/SkSizeHash.h"
+#include "platform/graphics/skia/SkSizeHash.h"
+#include "platform/image-decoders/ImageDecoder.h"
 
 #include "wtf/DoublyLinkedList.h"
 #include "wtf/HashSet.h"
@@ -82,7 +83,7 @@ class SharedBuffer;
 //
 // All public methods can be used on any thread.
 
-class ImageDecodingStore {
+class PLATFORM_EXPORT ImageDecodingStore {
 public:
     static PassOwnPtr<ImageDecodingStore> create() { return adoptPtr(new ImageDecodingStore); }
     ~ImageDecodingStore();