Adding |x|, |y|, |width| and |height| parameters copySubTextureCHROMIUM in WebGraphicsContext3D.

public/platform/WebGraphicsContext3D.h

Index: public/platform/WebGraphicsContext3D.h
diff --git a/public/platform/WebGraphicsContext3D.h b/public/platform/WebGraphicsContext3D.h
index 22fdb68ac3ad356d9f1cd8673e8bca6642bbb7c6..681b562bbe9b393b92832dff38235e7d3932a27f 100644
--- a/public/platform/WebGraphicsContext3D.h
+++ b/public/platform/WebGraphicsContext3D.h
@@ -399,6 +399,11 @@ public:
     virtual void copyTextureCHROMIUM(WGC3Denum target, WGC3Duint sourceId,
         WGC3Duint destId, WGC3Denum internalFormat, WGC3Denum destType) { }
     virtual void copySubTextureCHROMIUM(WGC3Denum target, WGC3Duint sourceId,
+        WGC3Duint destId, WGC3Dint xoffset, WGC3Dint yoffset, WGC3Dint x,
+        WGC3Dint y, WGC3Dsizei width, WGC3Dsizei height) { }
+    // TODO(reveman): Remove method without |x|, |y|, |width|, |height|.
+    // crbug.com/490889
+    virtual void copySubTextureCHROMIUM(WGC3Denum target, WGC3Duint sourceId,
         WGC3Duint destId, WGC3Dint xoffset, WGC3Dint yoffset) { }
 
     // GL_CHROMIUM_shallow_flush