Convert visitedlink to use mojo.

android_webview/renderer/aw_content_renderer_client.cc

Index: android_webview/renderer/aw_content_renderer_client.cc
diff --git a/android_webview/renderer/aw_content_renderer_client.cc b/android_webview/renderer/aw_content_renderer_client.cc
index 5a7b385b6695e3b01c41e715596e3dc39348e1ab..830661ec87d306b34945682d78d52e861ead09da 100644
--- a/android_webview/renderer/aw_content_renderer_client.cc
+++ b/android_webview/renderer/aw_content_renderer_client.cc
@@ -40,6 +40,7 @@
 #include "net/base/escape.h"
 #include "net/base/net_errors.h"
 #include "services/shell/public/cpp/interface_provider.h"
+#include "services/shell/public/cpp/interface_registry.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 #include "third_party/WebKit/public/platform/WebURLError.h"
@@ -71,7 +72,9 @@ void AwContentRendererClient::RenderThreadStarted() {
   thread->AddObserver(aw_render_thread_observer_.get());
 
   visited_link_slave_.reset(new visitedlink::VisitedLinkSlave);
-  thread->AddObserver(visited_link_slave_.get());
+  thread->GetInterfaceRegistry()->AddInterface(
+      base::Bind(&visitedlink::VisitedLinkSlave::Bind,
+                 base::Unretained(visited_link_slave_.get())));

[dcheng, 2016/09/20 22:29:27]

I am still uncomfortable that Mojo is encouraging wide use of base::Unretained()
in situations like this. In RenderThread or RenderFrame, it's somewhat easy to
verify that lifetimes are correct. But once impls start living in things that
aren't as tightly coupled, then the picture becomes significantly less clear: is
it possible for the InterfaceRegistry to outlive |this|?

We had several use-after-frees bugs last year due to base::Unretained() use that
"should have been safe" but weren't. Is there any possibility to just default to
refcounting impls that are reused? Alternatively, even using a WeakPtr would be
better. What would be the downside?

[Sam McNally, 2016/09/21 02:38:14]

Done.

 
   blink::WebString content_scheme(base::ASCIIToUTF16(url::kContentScheme));
   blink::WebSecurityPolicy::registerURLSchemeAsLocal(content_scheme);