Update browser manifest to require ProcessControl from gpu service

This adds a 'required' entry to the exe:content_browser manifest
for content::mojom::ProcessControl in exe:content_gpu, allowing
the browser to connect to the ProcessControl interface in the GPU
process.

Also fixes a bug in InterfaceRegistry which was causing useful
log errors to be omitted when capability filters would block
interface connection and registration.

BUG=624112
TBR=ben@chromium.org

Review-Url: https://codereview.chromium.org/2102353002
Cr-Commit-Position: refs/heads/master@{#402665}

content/public/app/mojo/content_browser_manifest.json

@@ -9,6 +9,9 @@
       "exe:content_renderer": {
         "interfaces": [ "content::mojom::RenderWidgetWindowTreeClientFactory" ]
       },
+      "exe:content_gpu": {
+        "interfaces": [ "content::mojom::ProcessControl" ]
+      },
       "mojo:shell": {
         "classes": [
           "shell:client_process",

services/shell/public/cpp/lib/interface_registry.cc

@@ -44,7 +44,7 @@ void InterfaceRegistry::GetInterface(const mojo::String& interface_name,
   auto iter = name_to_binder_.find(interface_name);
   if (iter != name_to_binder_.end()) {
     iter->second->BindInterface(connection_, interface_name, std::move(handle));
-  } else if (connection_ && connection_->AllowsInterface(interface_name)) {
+  } else if (connection_ && !connection_->AllowsInterface(interface_name)) {
     LOG(ERROR) << "Connection CapabilityFilter prevented binding to "
                << "interface: " << interface_name << " connection_name:"
                << connection_->GetConnectionName() << " remote_name:"