Adds support for headless chrome embedder mojo services

headless/lib/browser/headless_web_contents_impl.cc

Index: headless/lib/browser/headless_web_contents_impl.cc
diff --git a/headless/lib/browser/headless_web_contents_impl.cc b/headless/lib/browser/headless_web_contents_impl.cc
index 96c90ae99dadcb266392a12af636e1b76b2faabc..7a828a06de012c8dfed6f84a67187a5f4063f91c 100644
--- a/headless/lib/browser/headless_web_contents_impl.cc
+++ b/headless/lib/browser/headless_web_contents_impl.cc
@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/weak_ptr.h"
+#include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/browser/devtools_agent_host.h"
 #include "content/public/browser/navigation_handle.h"
@@ -16,7 +17,6 @@
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
-#include "content/public/browser/web_contents_observer.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/service_registry.h"
 #include "content/public/renderer/render_frame.h"
@@ -79,6 +79,10 @@ std::unique_ptr<HeadlessWebContentsImpl> HeadlessWebContentsImpl::Create(
       base::WrapUnique(new HeadlessWebContentsImpl(
           content::WebContents::Create(create_params), browser));
 
+  headless_web_contents->InstallMojoServices(
+      std::move(builder->mojo_services_));
+  headless_web_contents->InstallMojoBindings(
+      std::move(builder->mojo_bindings_));
   headless_web_contents->InitializeScreen(parent_window, builder->window_size_);
   if (!headless_web_contents->OpenURL(builder->initial_url_))
     return nullptr;
@@ -110,10 +114,37 @@ void HeadlessWebContentsImpl::InitializeScreen(aura::Window* parent_window,
     host_view->SetSize(initial_size);
 }
 
+void HeadlessWebContentsImpl::InstallMojoServices(
+    std::list<MojoService> mojo_services) {
+  if (mojo_services.empty())
+    return;
+
+  content::ServiceRegistry* service_registry =
+      web_contents_->GetRenderViewHost()->GetMainFrame()->GetServiceRegistry();
+
+  for (const MojoService& service : mojo_services) {
+    service_registry->AddService(service.service_name,
+                                 std::move(service.service_factory),
+                                 browser_->BrowserMainThread());
+  }
+}
+
+void HeadlessWebContentsImpl::InstallMojoBindings(
+    std::list<MojoBindings> mojo_bindings) {
+  mojo_bindings_ = std::move(mojo_bindings);
+
+  if (mojo_bindings_.empty())
+    return;
+
+  web_contents_->GetRenderViewHost()->AllowBindings(
+      content::BINDINGS_POLICY_MOJO);
+}
+
 HeadlessWebContentsImpl::HeadlessWebContentsImpl(
     content::WebContents* web_contents,
     HeadlessBrowserImpl* browser)
-    : web_contents_delegate_(new HeadlessWebContentsImpl::Delegate(browser)),
+    : content::WebContentsObserver(web_contents),
+      web_contents_delegate_(new HeadlessWebContentsImpl::Delegate(browser)),
       web_contents_(web_contents),
       browser_(browser) {
   web_contents_->SetDelegate(web_contents_delegate_.get());
@@ -123,6 +154,25 @@ HeadlessWebContentsImpl::~HeadlessWebContentsImpl() {
   web_contents_->Close();
 }
 
+void HeadlessWebContentsImpl::DocumentOnLoadCompletedInMainFrame() {
+  content::RenderFrameHost* render_frame_host = web_contents_->GetMainFrame();

[Sami, 2016/06/20 16:58:16]

Could you add a short comment saying why we need to do this at onload? (It was
because the mojo transport won't be available until document creation, right?)

[alex clarke (OOO till 29th), 2016/06/20 23:19:13]

Done.

+  std::string module_names;
+  bool first_binding = true;
+  for (const MojoBindings& binding : mojo_bindings_) {
+    render_frame_host->ExecuteJavaScriptForTests(
+        base::UTF8ToUTF16(binding.js_bindings));
+    if (first_binding) {
+      module_names = binding.mojom_name;

[Sami, 2016/06/20 16:58:16]

We should probably use base::GetQuotedJSONString() for safety. Another option
would be to construct a base::ListValue and turn that into a string.

[alex clarke (OOO till 29th), 2016/06/20 23:19:13]

Why would that improve safety?  These values come from browser process C++.

Another option

[Sami, 2016/06/21 10:22:26]

Sure, but they might be reading them from somewhere else and failing to verify.

+    } else {
+      module_names = module_names + "', '" + binding.mojom_name;

[Sami, 2016/06/20 16:58:16]

nit: base::JoinString might be a little neater.

[alex clarke (OOO till 29th), 2016/06/20 23:19:13]

I ended up using json writer.

+    }
+    first_binding = false;
+  }
+  // Note this function lets us run JS at anytime.

[Sami, 2016/06/20 16:58:16]

nit: as opposed to some other function? Maybe mention why we can't use the
non-test one?

[alex clarke (OOO till 29th), 2016/06/20 23:19:13]

Done.

+  render_frame_host->ExecuteJavaScriptForTests(base::UTF8ToUTF16(
+      "mojo.resolvePromisesForServices(['" + module_names + "']);"));
+}
+
 bool HeadlessWebContentsImpl::OpenURL(const GURL& url) {
   if (!url.is_valid())
     return false;
@@ -196,8 +246,41 @@ HeadlessWebContents::Builder& HeadlessWebContents::Builder::SetBrowserContext(
   return *this;
 }
 
+HeadlessWebContents::Builder& HeadlessWebContents::Builder::AddMojoService(
+    const std::string& service_name,
+    const base::Callback<void(mojo::ScopedMessagePipeHandle)>&
+        service_factory) {
+  mojo_services_.emplace_back(service_name, service_factory);
+  return *this;
+}
+
+HeadlessWebContents::Builder& HeadlessWebContents::Builder::AddJsMojoBindings(
+    const std::string& mojom_name,
+    const std::string& js_bindings) {
+  mojo_bindings_.emplace_back(mojom_name, js_bindings);
+  return *this;
+}
+
 HeadlessWebContents* HeadlessWebContents::Builder::Build() {
   return browser_->CreateWebContents(this);
 }
 
+HeadlessWebContents::Builder::MojoService::MojoService() {}
+
+HeadlessWebContents::Builder::MojoService::MojoService(
+    const std::string& service_name,
+    const base::Callback<void(mojo::ScopedMessagePipeHandle)>& service_factory)
+    : service_name(service_name), service_factory(service_factory) {}
+
+HeadlessWebContents::Builder::MojoService::~MojoService() {}
+
+HeadlessWebContents::Builder::MojoBindings::MojoBindings() {}
+
+HeadlessWebContents::Builder::MojoBindings::MojoBindings(
+    const std::string& mojom_name,
+    const std::string& js_bindings)
+    : mojom_name(mojom_name), js_bindings(js_bindings) {}
+
+HeadlessWebContents::Builder::MojoBindings::~MojoBindings() {}
+
 }  // namespace headless