Return the shared context's handle when a virtualized context's

handle is requested.

GLES2DecoderImpl::DoTexImageIOSurface2DCHROMIUM uses
GLContext::GetHandle's result as an argument to 
CGLTexImageIOSurface2D, which expects a valid CGLContextObj
as the handle (not NULL).

BUG=230300

Review URL: https://chromiumcodereview.appspot.com/14241007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195390 0039d316-1c4b-4281-b951-d872f2087c98

gpu/command_buffer/service/gl_context_virtual.cc

@@ -73,7 +73,7 @@ bool GLContextVirtual::IsCurrent(gfx::GLSurface* surface) {
 }
 
 void* GLContextVirtual::GetHandle() {
-  return NULL;
+  return shared_context_->GetHandle();
 }
 
 gfx::GLStateRestorer* GLContextVirtual::GetGLStateRestorer() {