Adds a way to determine id of content handler that created app

components/pdf_viewer/pdf_viewer.cc

Index: components/pdf_viewer/pdf_viewer.cc
diff --git a/components/pdf_viewer/pdf_viewer.cc b/components/pdf_viewer/pdf_viewer.cc
index 730ce3a27ea6be565f127a52b1d7e68d5feec614..fbdd506a6f38552af9e92be819c58403b14ca964 100644
--- a/components/pdf_viewer/pdf_viewer.cc
+++ b/components/pdf_viewer/pdf_viewer.cc
@@ -53,6 +53,8 @@ void LostContext(void*) {
   DCHECK(false);
 }
 
+void OnGotContentHandlerID(uint32_t content_handler_id) {}
+
 // BitmapUploader is useful if you want to draw a bitmap or color in a View.
 class BitmapUploader : public mojo::SurfaceClient {
  public:
@@ -79,7 +81,7 @@ class BitmapUploader : public mojo::SurfaceClient {
     request2->url = mojo::String::From("mojo:view_manager");
     shell->ConnectToApplication(request2.Pass(),
                                 mojo::GetProxy(&gpu_service_provider), nullptr,
-                                nullptr);
+                                nullptr, base::Bind(&OnGotContentHandlerID));
     ConnectToService(gpu_service_provider.get(), &gpu_service_);
 
     mojo::CommandBufferPtr gles2_client;