Moving GraphicsContext and dependencies from core to platform.

Source/platform/scroll/ScrollbarThemeOverlayMock.h

Index: Source/platform/scroll/ScrollbarThemeOverlayMock.h
diff --git a/Source/core/platform/mock/ScrollbarThemeOverlayMock.h b/Source/platform/scroll/ScrollbarThemeOverlayMock.h
similarity index 93%
rename from Source/core/platform/mock/ScrollbarThemeOverlayMock.h
rename to Source/platform/scroll/ScrollbarThemeOverlayMock.h
index 0a9a862dd85ccdb4904d39282819d88e90891328..ecbba083bb96487a53f0383819b1b20a684c78d7 100644
--- a/Source/core/platform/mock/ScrollbarThemeOverlayMock.h
+++ b/Source/platform/scroll/ScrollbarThemeOverlayMock.h
@@ -31,11 +31,11 @@
 #ifndef ScrollbarThemeOverlayMock_h
 #define ScrollbarThemeOverlayMock_h
 
-#include "core/platform/ScrollbarThemeOverlay.h"
+#include "platform/scroll/ScrollbarThemeOverlay.h"
 
 namespace WebCore {
 
-class ScrollbarThemeOverlayMock : public ScrollbarThemeOverlay {
+class PLATFORM_EXPORT ScrollbarThemeOverlayMock : public ScrollbarThemeOverlay {
 public:
     ScrollbarThemeOverlayMock() : ScrollbarThemeOverlay(3, 4, DisallowHitTest, Color(128, 128, 128)) { }