Make Mandoline shut down cleanly.

components/native_viewport/onscreen_context_provider.cc

Index: components/native_viewport/onscreen_context_provider.cc
diff --git a/components/native_viewport/onscreen_context_provider.cc b/components/native_viewport/onscreen_context_provider.cc
index 7d6b5bfdd531c0bb5fd1995934d61e01043db94f..ec9cc530338e5df03e1aceb172475e046db1c79e 100644
--- a/components/native_viewport/onscreen_context_provider.cc
+++ b/components/native_viewport/onscreen_context_provider.cc
@@ -4,6 +4,7 @@
 
 #include "components/native_viewport/onscreen_context_provider.h"
 
+#include "base/bind.h"
 #include "components/gles2/command_buffer_driver.h"
 #include "components/gles2/command_buffer_impl.h"
 #include "components/gles2/gpu_state.h"
@@ -12,10 +13,14 @@ namespace native_viewport {
 
 OnscreenContextProvider::OnscreenContextProvider(
     const scoped_refptr<gles2::GpuState>& state)
-    : state_(state), widget_(gfx::kNullAcceleratedWidget), binding_(this) {
+    : state_(state),
+      widget_(gfx::kNullAcceleratedWidget),
+      binding_(this) {
 }
 
 OnscreenContextProvider::~OnscreenContextProvider() {
+  for (const auto& driver : command_buffers_)
+    driver->DestroyWindow();
 }
 
 void OnscreenContextProvider::Bind(
@@ -45,14 +50,25 @@ void OnscreenContextProvider::Create(
 
 void OnscreenContextProvider::CreateAndReturnCommandBuffer() {
   mojo::CommandBufferPtr cb;
+  scoped_ptr<gles2::CommandBufferDriver> command_buffer_driver(
+      new gles2::CommandBufferDriver(
+          widget_, state_->share_group(), state_->mailbox_manager(),
+          state_->sync_point_manager(),
+          base::Bind(&OnscreenContextProvider::CommandBufferDestroyed,
+                     base::Unretained(this))));
+  command_buffers_.insert(command_buffer_driver.get());
+
   new gles2::CommandBufferImpl(
       GetProxy(&cb), pending_listener_.Pass(), state_->control_task_runner(),
       state_->sync_point_manager(),
-      make_scoped_ptr(new gles2::CommandBufferDriver(
-          widget_, state_->share_group(), state_->mailbox_manager(),
-          state_->sync_point_manager())));
+      command_buffer_driver.Pass());
   pending_create_callback_.Run(cb.Pass());
   pending_create_callback_.reset();
 }
 
+void OnscreenContextProvider::CommandBufferDestroyed(
+    gles2::CommandBufferDriver* command_buffer) {
+  command_buffers_.erase(command_buffer);
+}
+
 }  // namespace mojo