Moving GraphicsContext and dependencies from core to platform.

Source/platform/graphics/gpu/SharedGraphicsContext3D.h

Index: Source/platform/graphics/gpu/SharedGraphicsContext3D.h
diff --git a/Source/core/platform/graphics/gpu/SharedGraphicsContext3D.h b/Source/platform/graphics/gpu/SharedGraphicsContext3D.h
similarity index 93%
rename from Source/core/platform/graphics/gpu/SharedGraphicsContext3D.h
rename to Source/platform/graphics/gpu/SharedGraphicsContext3D.h
index 4525ee80cd07ce7141c66eaa7d7e23c2496a80a1..47ace4a032a503430665709f8d563290d9714dcc 100644
--- a/Source/core/platform/graphics/gpu/SharedGraphicsContext3D.h
+++ b/Source/platform/graphics/gpu/SharedGraphicsContext3D.h
@@ -26,13 +26,14 @@
 #ifndef SharedGraphicsContext3D_h
 #define SharedGraphicsContext3D_h
 
-#include "core/platform/graphics/GraphicsContext3D.h"
+#include "platform/PlatformExport.h"
+#include "platform/graphics/GraphicsContext3D.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 
 namespace WebCore {
 
-class SharedGraphicsContext3D {
+class PLATFORM_EXPORT SharedGraphicsContext3D {
 public:
     // The caller may ref this pointer, and hang onto it as long as they like.
     // However, the context should be checked periodically to determine if it