gpu: Extend CopyTextureCHROMIUM with support for copying part of source texture.

gpu/blink/webgraphicscontext3d_impl.h

Index: gpu/blink/webgraphicscontext3d_impl.h
diff --git a/gpu/blink/webgraphicscontext3d_impl.h b/gpu/blink/webgraphicscontext3d_impl.h
index 552f5fb286ecef043dc3b69e800eb318f4dc2278..b11c1f483648d21d7ffefb6df04098a3ccf63ec7 100644
--- a/gpu/blink/webgraphicscontext3d_impl.h
+++ b/gpu/blink/webgraphicscontext3d_impl.h
@@ -528,7 +528,11 @@ class GPU_BLINK_EXPORT WebGraphicsContext3DImpl
                               blink::WebGLId source_id,
                               blink::WebGLId dest_id,
                               blink::WGC3Dint xoffset,
-                              blink::WGC3Dint yoffset) override;
+                              blink::WGC3Dint yoffset,
+                              blink::WGC3Dint x,
+                              blink::WGC3Dint y,
+                              blink::WGC3Dsizei width,
+                              blink::WGC3Dsizei height) override;
 
   virtual void bindUniformLocationCHROMIUM(blink::WebGLId program,
                                            blink::WGC3Dint location,