Tell Graphics3D not to lock on Flush().

ppapi/shared_impl/ppb_video_decoder_shared.cc

Index: ppapi/shared_impl/ppb_video_decoder_shared.cc
===================================================================
--- ppapi/shared_impl/ppb_video_decoder_shared.cc	(revision 175266)
+++ ppapi/shared_impl/ppb_video_decoder_shared.cc	(working copy)
@@ -7,6 +7,7 @@
 #include "base/logging.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "ppapi/c/pp_errors.h"
+#include "ppapi/shared_impl/ppb_graphics_3d_shared.h"
 #include "ppapi/shared_impl/resource_tracker.h"
 #include "ppapi/thunk/enter.h"
 
@@ -90,8 +91,16 @@
 }
 
 void PPB_VideoDecoder_Shared::FlushCommandBuffer() {
-  if (gles2_impl_)
+  if (gles2_impl_) {

[Scott Hess - ex-Googler, 2013/01/07 22:41:02]

This looks broadly like what I expected it to look like, BUT I cannot tell if
this is the right place for it.  It seems like the _shared code shouldn't refer
out to proxy-related stuff like this.  Instead maybe ppb_video_decoder_proxy.cc
code should call something like FlushCommandBufferWhileLocked() [or something]
which does the ScopedNoLocking and then calls this FlushCommandBuffer().  Maybe.

Or make FlushCommandBuffer() virtual and do it that way, I do not know.  It just
feels like the proxy-lock-specific code belongs with the _proxy, so that it
doesn't run in the _impl.

+    // To call Flush() we have to tell Graphics3D that we hold the proxy lock.
+    thunk::EnterResource<thunk::PPB_Graphics3D_API, false> enter_g3d(
+        graphics_context_, false);
+    DCHECK(enter_g3d.succeeded());
+    PPB_Graphics3D_Shared* graphics3d =
+        static_cast<PPB_Graphics3D_Shared*>(enter_g3d.object());
+    PPB_Graphics3D_Shared::ScopedNoLocking dont_lock(graphics3d);
     gles2_impl_->Flush();
+  }
 }
 
 }  // namespace ppapi