[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/output/delegating_renderer.cc

Index: cc/output/delegating_renderer.cc
diff --git a/cc/output/delegating_renderer.cc b/cc/output/delegating_renderer.cc
index c76f250754a8036a8a379bfdccef66af19e2eac0..73cbc9a884a280cfd891802da9c68aaf09a460c2 100644
--- a/cc/output/delegating_renderer.cc
+++ b/cc/output/delegating_renderer.cc
@@ -96,8 +96,8 @@ static ResourceProvider::ResourceId AppendToArray(
 void DelegatingRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
                                    ContextProvider* offscreen_context_provider,
                                    float device_scale_factor,
-                                   gfx::Rect device_viewport_rect,
-                                   gfx::Rect device_clip_rect,
+                                   const gfx::Rect& device_viewport_rect,
+                                   const gfx::Rect& device_clip_rect,
                                    bool allow_partial_swap,
                                    bool disable_picture_quad_image_filtering) {
   TRACE_EVENT0("cc", "DelegatingRenderer::DrawFrame");
@@ -129,7 +129,8 @@ void DelegatingRenderer::SwapBuffers(const CompositorFrameMetadata& metadata) {
   output_surface_->SwapBuffers(&compositor_frame);
 }
 
-void DelegatingRenderer::GetFramebufferPixels(void* pixels, gfx::Rect rect) {
+void DelegatingRenderer::GetFramebufferPixels(void* pixels,
+                                              const gfx::Rect& rect) {
   NOTREACHED();
 }