Ignore custom offscreen surface unless explicitly opted in

gpu/ipc/service/gpu_command_buffer_stub.cc

Index: gpu/ipc/service/gpu_command_buffer_stub.cc
diff --git a/gpu/ipc/service/gpu_command_buffer_stub.cc b/gpu/ipc/service/gpu_command_buffer_stub.cc
index 6d305cf9ab99b670e9d8c743e9ad21c6cbd1161d..3880471c187d9058f1411da6f56d13469eebb0b7 100644
--- a/gpu/ipc/service/gpu_command_buffer_stub.cc
+++ b/gpu/ipc/service/gpu_command_buffer_stub.cc
@@ -655,6 +655,15 @@ bool GpuCommandBufferStub::Initialize(
   decoder_->set_engine(executor_.get());
 
   if (offscreen) {
+#if defined(OS_ANDROID)
+    // This code isn't really platform specific, but apparently NaCl
+    // plugins on Ozone requested custom attributes for offscreen
+    // surfaces even though there is no implementation to apply these
+    // features. For now, continue ignoring the attributes for

[jbauman, 2017/03/21 00:51:41]

I think what's happening with NaCL is that the GLES2CmdDecoder uses the params
to create its offscreen backbuffer. That's normally how this is supposed to work
- offscreen command-buffers create textures and draw on them, rather than using
the surface itself. So we should be using some sort of flag to say that it's
actually going to draw into Surface rather into its own texture.

+    // backwards compatibility. TODO(klausw,crbug.com/699664): remove
+    // the Android conditional once it's generally supported, and/or
+    // add a separate use_own_surface boolean attribute to make this
+    // explicitly opt-in.
     if (init_params.attribs.depth_size > 0) {
       surface_format.SetDepthBits(init_params.attribs.depth_size);
     }
@@ -664,6 +673,7 @@ bool GpuCommandBufferStub::Initialize(
     if (init_params.attribs.stencil_size > 0) {
       surface_format.SetStencilBits(init_params.attribs.stencil_size);
     }
+#endif
     // Currently, we can't separately control alpha channel for surfaces,
     // it's generally enabled by default except for RGB565 and (on desktop)
     // smaller-than-32bit formats.