Moving GraphicsContext and dependencies from core to platform.

Source/platform/graphics/GraphicsContext3D.h

Index: Source/platform/graphics/GraphicsContext3D.h
diff --git a/Source/core/platform/graphics/GraphicsContext3D.h b/Source/platform/graphics/GraphicsContext3D.h
similarity index 99%
rename from Source/core/platform/graphics/GraphicsContext3D.h
rename to Source/platform/graphics/GraphicsContext3D.h
index f976a12cb8e806aef681a74b3f4a5d602c869a65..1a2e6a246d16139d6ce5b42eda09b71ab1679579 100644
--- a/Source/core/platform/graphics/GraphicsContext3D.h
+++ b/Source/platform/graphics/GraphicsContext3D.h
@@ -26,10 +26,11 @@
 #ifndef GraphicsContext3D_h
 #define GraphicsContext3D_h
 
-#include "core/platform/graphics/Extensions3D.h"
-#include "core/platform/graphics/Image.h"
+#include "platform/PlatformExport.h"
 #include "platform/geometry/IntRect.h"
+#include "platform/graphics/Extensions3D.h"
 #include "platform/graphics/GraphicsTypes3D.h"
+#include "platform/graphics/Image.h"
 #include "platform/weborigin/KURL.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "wtf/HashMap.h"
@@ -69,7 +70,7 @@ struct ActiveInfo {
     GC3Dint size;
 };
 
-class GraphicsContext3D : public RefCounted<GraphicsContext3D> {
+class PLATFORM_EXPORT GraphicsContext3D : public RefCounted<GraphicsContext3D> {
 public:
     enum {
         DEPTH_BUFFER_BIT = 0x00000100,
@@ -733,7 +734,7 @@ public:
         HtmlDomNone = 3
     };
 
-    class ImageExtractor {
+    class PLATFORM_EXPORT ImageExtractor {
     public:
         ImageExtractor(Image*, ImageHtmlDomSource, bool premultiplyAlpha, bool ignoreGammaAndColorProfile);