cc: Make OutputSurface::Reshape abstract

cc/test/fake_output_surface.h

Index: cc/test/fake_output_surface.h
diff --git a/cc/test/fake_output_surface.h b/cc/test/fake_output_surface.h
index a0aa77bf8c283691ee6b658b945630e08c7ada89..b90a1f3b07b101bdbdeea99b8cb95ec16adc299c 100644
--- a/cc/test/fake_output_surface.h
+++ b/cc/test/fake_output_surface.h
@@ -73,6 +73,10 @@ class FakeOutputSurface : public OutputSurface {
   void EnsureBackbuffer() override {}
   void DiscardBackbuffer() override {}
   void BindFramebuffer() override;
+  void Reshape(const gfx::Size& size,
+               float device_scale_factor,
+               const gfx::ColorSpace& color_space,
+               bool has_alpha) override;
   void SwapBuffers(OutputSurfaceFrame frame) override;
   uint32_t GetFramebufferCopyTextureFormat() override;
   bool HasExternalStencilTest() const override;