Fix crash when backgrounding MojoShell on Android. Fixes issue #186.

services/native_viewport/onscreen_context_provider.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/native_viewport/onscreen_context_provider.h"
 
 #include "services/gles2/command_buffer_driver.h"
 #include "services/gles2/gpu_state.h"
 
 namespace native_viewport {
@@ skipping 14 matching lines @@
 void OnscreenContextProvider::Bind(
     mojo::InterfaceRequest<mojo::ContextProvider> request) {
   binding_.Bind(request.Pass());
 }
 
 void OnscreenContextProvider::SetAcceleratedWidget(
     gfx::AcceleratedWidget widget) {
   widget_ = widget;
 
   if (widget_ == gfx::kNullAcceleratedWidget) {
-    if (command_buffer_impl_)
+    if (command_buffer_impl_) {
       command_buffer_impl_->DidLoseContext();
+    }
     return;
   }
 
   if (pending_create_callback_.is_null())
     return;
 
   CreateAndReturnCommandBuffer();
 }
 
 void OnscreenContextProvider::Create(
@@ skipping 22 matching lines @@
       state_->sync_point_manager(),
       make_scoped_ptr(new gles2::CommandBufferDriver(
           widget_, state_->share_group(), state_->mailbox_manager(),
           state_->sync_point_manager())));
   command_buffer_impl_->set_observer(this);
   pending_create_callback_.Run(cb.Pass());
   pending_create_callback_.reset();
 }
 
 }  // namespace mojo