Add the necessary plumbing mechanisms to ensure proper WebGL support inside the <browser> tag, whic…

ppapi/proxy/ppb_graphics_3d_proxy.cc

Index: ppapi/proxy/ppb_graphics_3d_proxy.cc
diff --git a/ppapi/proxy/ppb_graphics_3d_proxy.cc b/ppapi/proxy/ppb_graphics_3d_proxy.cc
index 2a708a36dbd49d4bdf0a694722c8d040c09e99a5..671b60cbe27e8798c1d9e1662e315e61750ae8da 100644
--- a/ppapi/proxy/ppb_graphics_3d_proxy.cc
+++ b/ppapi/proxy/ppb_graphics_3d_proxy.cc
@@ -146,17 +146,12 @@ PPB_Graphics3D_Proxy::~PPB_Graphics3D_Proxy() {
 // static
 PP_Resource PPB_Graphics3D_Proxy::CreateProxyResource(
     PP_Instance instance,
-    PP_Resource share_context,
+    PPB_Graphics3D_API* share_context,
     const int32_t* attrib_list) {
   PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
   if (!dispatcher)
     return PP_ERROR_BADARGUMENT;
 
-  // TODO(alokp): Support shared context.
-  DCHECK_EQ(0, share_context);
-  if (share_context != 0)
-    return 0;
-
   std::vector<int32_t> attribs;
   if (attrib_list) {
     for (const int32_t* attr = attrib_list;
@@ -168,9 +163,13 @@ PP_Resource PPB_Graphics3D_Proxy::CreateProxyResource(
   }
   attribs.push_back(PP_GRAPHICS3DATTRIB_NONE);
 
+  HostResource share_host;
+  if (share_context)
+    share_host = static_cast<Graphics3D*>(share_context)->host_resource();
+
   HostResource result;
   dispatcher->Send(new PpapiHostMsg_PPBGraphics3D_Create(
-      API_ID_PPB_GRAPHICS_3D, instance, attribs, &result));
+      API_ID_PPB_GRAPHICS_3D, instance, share_host, attribs, &result));
   if (result.is_null())
     return 0;
 
@@ -214,16 +213,28 @@ bool PPB_Graphics3D_Proxy::OnMessageReceived(const IPC::Message& msg) {
 }
 
 void PPB_Graphics3D_Proxy::OnMsgCreate(PP_Instance instance,
+                                       HostResource share_context,
                                        const std::vector<int32_t>& attribs,
                                        HostResource* result) {
   if (attribs.empty() || attribs.back() != PP_GRAPHICS3DATTRIB_NONE)
     return;  // Bad message.
 
   thunk::EnterResourceCreation enter(instance);
+  PPB_Graphics3D_API *share_api = NULL;
+  if (share_context.host_resource() != 0) {
+    thunk::EnterResource<thunk::PPB_Graphics3D_API>
+        enter_share(share_context.host_resource(), true);
+    if (!enter_share.succeeded())
+      return;
+    share_api = enter_share.object();
+  }
+
   if (enter.succeeded()) {
     result->SetHostResource(
-        instance,
-        enter.functions()->CreateGraphics3DRaw(instance, 0, &attribs.front()));
+      instance,
+      enter.functions()->CreateGraphics3DRaw(instance,
+                                             share_api,
+                                             &attribs.front()));
   }
 }