Mojo multiple command buffer support and sample

mojo/services/native_viewport/native_viewport_service.cc

Index: mojo/services/native_viewport/native_viewport_service.cc
diff --git a/mojo/services/native_viewport/native_viewport_service.cc b/mojo/services/native_viewport/native_viewport_service.cc
index 2903de0b441fa19a33937faa6836227f028ae2bd..3e53bd3520d29c5fb6744f36a080d9073de3bd2f 100644
--- a/mojo/services/native_viewport/native_viewport_service.cc
+++ b/mojo/services/native_viewport/native_viewport_service.cc
@@ -8,6 +8,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/time/time.h"
+#include "gpu/command_buffer/service/mailbox_manager.h"
 #include "mojo/public/cpp/application/application_delegate.h"
 #include "mojo/public/cpp/application/interface_factory.h"
 #include "mojo/services/gles2/command_buffer_impl.h"
@@ -16,6 +17,7 @@
 #include "mojo/services/public/cpp/input_events/input_events_type_converters.h"
 #include "mojo/services/public/interfaces/native_viewport/native_viewport.mojom.h"
 #include "ui/events/event.h"
+#include "ui/gl/gl_share_group.h"
 
 namespace mojo {
 namespace services {
@@ -32,9 +34,13 @@ bool IsRateLimitedEventType(ui::Event* event) {
 class NativeViewportImpl : public InterfaceImpl<mojo::NativeViewport>,
                            public NativeViewportDelegate {
  public:
-  NativeViewportImpl()
+  NativeViewportImpl(
+      const scoped_refptr<gfx::GLShareGroup>& share_group,
+      const scoped_refptr<gpu::gles2::MailboxManager>& mailbox_manager)
       : widget_(gfx::kNullAcceleratedWidget),
         waiting_for_event_ack_(false),
+        share_group_(share_group),
+        mailbox_manager_(mailbox_manager),
         weak_factory_(this) {}
   virtual ~NativeViewportImpl() {
     // Destroy the NativeViewport early on as it may call us back during
@@ -77,6 +83,13 @@ class NativeViewportImpl : public InterfaceImpl<mojo::NativeViewport>,
     CreateCommandBufferIfNeeded();
   }
 
+  virtual void CreateOffscreenGLES2Context(
+      InterfaceRequest<CommandBuffer> command_buffer_request) OVERRIDE {
+    BindToRequest(
+        new CommandBufferImpl(share_group_.get(), mailbox_manager_.get()),
+        &command_buffer_request);
+  }
+
   void AckEvent() {
     waiting_for_event_ack_ = false;
   }
@@ -90,8 +103,10 @@ class NativeViewportImpl : public InterfaceImpl<mojo::NativeViewport>,
     gfx::Size size = native_viewport_->GetSize();
     if (size.IsEmpty())
       return;
-    command_buffer_.reset(
-        new CommandBufferImpl(widget_, native_viewport_->GetSize()));
+    command_buffer_.reset(new CommandBufferImpl(widget_,
+                                                native_viewport_->GetSize(),
+                                                share_group_.get(),
+                                                mailbox_manager_.get()));
     WeakBindToRequest(command_buffer_.get(), &command_buffer_request_);
   }
 
@@ -147,13 +162,17 @@ class NativeViewportImpl : public InterfaceImpl<mojo::NativeViewport>,
   InterfaceRequest<CommandBuffer> command_buffer_request_;
   scoped_ptr<CommandBufferImpl> command_buffer_;
   bool waiting_for_event_ack_;
+  scoped_refptr<gfx::GLShareGroup> share_group_;
+  scoped_refptr<gpu::gles2::MailboxManager> mailbox_manager_;
   base::WeakPtrFactory<NativeViewportImpl> weak_factory_;
 };
 
 class NVSDelegate : public ApplicationDelegate,
                     public InterfaceFactory<mojo::NativeViewport> {
  public:
-  NVSDelegate() {}
+  NVSDelegate()
+      : share_group_(new gfx::GLShareGroup),
+        mailbox_manager_(new gpu::gles2::MailboxManager) {}
   virtual ~NVSDelegate() {}
 
   // ApplicationDelegate implementation.
@@ -166,8 +185,16 @@ class NVSDelegate : public ApplicationDelegate,
   // ServiceFactory<mojo::NativeViewport> implementation.
   virtual void Create(ApplicationConnection* connection,
                       InterfaceRequest<mojo::NativeViewport> request) OVERRIDE {
-    BindToRequest(new NativeViewportImpl, &request);
+    BindToRequest(
+        new NativeViewportImpl(share_group_.get(), mailbox_manager_.get()),
+        &request);
   }
+
+ private:
+  // We need to share these across all NativeViewport instances so that contexts
+  // they create can share resources with each other via mailboxes.
+  scoped_refptr<gfx::GLShareGroup> share_group_;
+  scoped_refptr<gpu::gles2::MailboxManager> mailbox_manager_;
 };
 
 MOJO_NATIVE_VIEWPORT_EXPORT mojo::ApplicationImpl*