Make CommandBuffer::Flush asynchronous, and add CommandBuffer::FlushSync with former semantics.

chrome/renderer/webplugin_delegate_pepper.cc

Index: chrome/renderer/webplugin_delegate_pepper.cc
diff --git a/chrome/renderer/webplugin_delegate_pepper.cc b/chrome/renderer/webplugin_delegate_pepper.cc
index b5d6d1f2e7bbbc7d12b2bf6ceb4c34cdab449bcb..1f8faaaf4c8664c39eafc8f794e74b10232e5f30 100644
--- a/chrome/renderer/webplugin_delegate_pepper.cc
+++ b/chrome/renderer/webplugin_delegate_pepper.cc
@@ -779,7 +779,7 @@ NPError WebPluginDelegatePepper::Device3DFlushContext(
               callback,
               user_data));
     } else {
-      state = command_buffer_->Flush(context->putOffset);
+      state = command_buffer_->FlushSync(context->putOffset);
       Synchronize3DContext(context, state);
     }
   } else {