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..323dfdc274a455c97b7ff8d6270cd60253190b15 100644
--- a/ppapi/proxy/ppb_graphics_3d_proxy.cc
+++ b/ppapi/proxy/ppb_graphics_3d_proxy.cc
@@ -69,7 +69,7 @@ Graphics3D::~Graphics3D() {
   DestroyGLES2Impl();
 }
 
-bool Graphics3D::Init() {
+bool Graphics3D::Init(gpu::gles2::GLES2Implementation *share_gles2) {
   PluginDispatcher* dispatcher = PluginDispatcher::GetForResource(this);
   if (!dispatcher)
     return false;
@@ -79,7 +79,8 @@ bool Graphics3D::Init() {
   if (!command_buffer_->Initialize())
     return false;
 
-  return CreateGLES2Impl(kCommandBufferSize, kTransferBufferSize);
+  return CreateGLES2Impl(kCommandBufferSize, kTransferBufferSize,
+                         share_gles2);
 }
 
 PP_Bool Graphics3D::InitCommandBuffer() {
@@ -146,16 +147,19 @@ 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);
+  Graphics3D* share_graphics = static_cast<Graphics3D*>(share_context);
   if (!dispatcher)
     return PP_ERROR_BADARGUMENT;
 
-  // TODO(alokp): Support shared context.
-  DCHECK_EQ(0, share_context);
-  if (share_context != 0)
-    return 0;
+  HostResource share_host;
+  gpu::gles2::GLES2Implementation* share_gles2 = NULL;
+  if (share_context) {
+    share_host = share_graphics->host_resource();
+    share_gles2 = share_graphics->gles2_impl();
+  }
 
   std::vector<int32_t> attribs;
   if (attrib_list) {
@@ -170,12 +174,12 @@ PP_Resource PPB_Graphics3D_Proxy::CreateProxyResource(
 
   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;
 
   scoped_refptr<Graphics3D> graphics_3d(new Graphics3D(result));
-  if (!graphics_3d->Init())
+  if (!graphics_3d->Init(share_gles2))
     return 0;
   return graphics_3d->GetReference();
 }
@@ -214,16 +218,28 @@ 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()));
   }
 }