gpu: Add CHROMIUM_copy_image extension.

gpu/command_buffer/service/texture_manager_unittest.cc

Index: gpu/command_buffer/service/texture_manager_unittest.cc
diff --git a/gpu/command_buffer/service/texture_manager_unittest.cc b/gpu/command_buffer/service/texture_manager_unittest.cc
index c0aa539f4e52d8a4ebdff2706828ddc87faf04a7..dd914b2e895ef31598b9bb7d99aabf1af0f25df2 100644
--- a/gpu/command_buffer/service/texture_manager_unittest.cc
+++ b/gpu/command_buffer/service/texture_manager_unittest.cc
@@ -160,6 +160,13 @@ class GLStreamTextureImageStub : public GLStreamTextureImage {
                        const gfx::Rect& rect) override {
     return false;
   }
+  bool CopySubImageData(unsigned texture_id,
+                        const gfx::Point& offset,
+                        const gfx::Rect& rect,
+                        gl::GLFence* in_fence,
+                        gl::GLFence* out_fence) override {
+    return false;
+  }
   bool ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                             int z_order,
                             gfx::OverlayTransform transform,