Enable partial texture upload support for browser compositor with Surfaces

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 c05c32f2abbc66941800d49ba78d09ec99da4261..75fc2d6c54f21836d83ebe7626b52133e20234d1 100644
--- a/cc/output/delegating_renderer.cc
+++ b/cc/output/delegating_renderer.cc
@@ -41,7 +41,8 @@ DelegatingRenderer::DelegatingRenderer(RendererClient* client,
   capabilities_.using_partial_swap = false;
   capabilities_.max_texture_size = resource_provider_->max_texture_size();
   capabilities_.best_texture_format = resource_provider_->best_texture_format();
-  capabilities_.allow_partial_texture_updates = false;
+  capabilities_.allow_partial_texture_updates =

[danakj, 2015/01/09 01:11:12]

Thanks, this LGTM for non-impl-side painting. (I didn't really look at the
cc/surfaces/ parts, james can review those?)

What happens when implside gets turned on in the browser and this capability is
present? Should we only turn this allow_ptt_updates when implside is off? What's
the right way to stage this?

+      output_surface->capabilities().can_force_reclaim_resources;
 
   if (!output_surface_->context_provider()) {
     capabilities_.using_shared_memory_resources = true;