Partial swap implementation for surfaceless

ui/gl/gl_surface_ozone.cc

Index: ui/gl/gl_surface_ozone.cc
diff --git a/ui/gl/gl_surface_ozone.cc b/ui/gl/gl_surface_ozone.cc
index 0c30c20ba0a578206ae85103637afcfea4c94b18..7a602979e1cad5fa3420dbea4b4e41f08a7ee33d 100644
--- a/ui/gl/gl_surface_ozone.cc
+++ b/ui/gl/gl_surface_ozone.cc
@@ -138,6 +138,13 @@ class GL_EXPORT GLSurfaceOzoneSurfaceless : public SurfacelessEGL {
   virtual VSyncProvider* GetVSyncProvider() OVERRIDE {
     return vsync_provider_.get();
   }
+  virtual bool SupportsPostSubBuffer() OVERRIDE { return true; }

[alexst (slow to review), 2014/09/17 20:34:06]

This is shared between surfaceless and surfaced, so I don't think we can just
return true here. It's reasonable to enable it in surfaceless by default, but we
need to check that we are surfaceless here.

[achaulk, 2014/09/17 20:41:57]

No this is the surfaceless class

+  virtual bool PostSubBuffer(int x, int y, int width, int height) OVERRIDE {
+    // The actual sub buffer handling is handled at higher layers. We need to
+    // return true to SupportsPostSubBuffer to enable it, but we should never
+    // actually get the sub-buffer swap.

[alexst (slow to review), 2014/09/17 20:34:06]

If we are not expected to be here, we should add NOTREACHED()

[achaulk, 2014/09/17 20:41:57]

Done.

+    return false;
+  }
 
  private:
   virtual ~GLSurfaceOzoneSurfaceless() {