Filters out URL clicks based on host matching only.

chrome/browser/chromeos/arc/arc_navigation_throttle.cc

Index: chrome/browser/chromeos/arc/arc_navigation_throttle.cc
diff --git a/chrome/browser/chromeos/arc/arc_navigation_throttle.cc b/chrome/browser/chromeos/arc/arc_navigation_throttle.cc
index 3e3a3abe8a00cdb53d13b0997a9b216add21a3dc..fd41e629103ec58beab07bb660c20a05c9983b38 100644
--- a/chrome/browser/chromeos/arc/arc_navigation_throttle.cc
+++ b/chrome/browser/chromeos/arc/arc_navigation_throttle.cc
@@ -65,6 +65,9 @@ ArcNavigationThrottle::WillStartRequest() {
   if (!navigation_handle()->HasUserGesture())
     return content::NavigationThrottle::PROCEED;
 
+  if (!ShouldOverrideUrlLoading())
+    return content::NavigationThrottle::PROCEED;
+
   const GURL& url = navigation_handle()->GetURL();
   mojom::IntentHelperInstance* bridge_instance = GetIntentHelper();
   if (!bridge_instance)
@@ -207,4 +210,12 @@ void ArcNavigationThrottle::OnDisambigDialogClosed(
                             static_cast<int>(CloseReason::SIZE));
 }
 
+bool ArcNavigationThrottle::ShouldOverrideUrlLoading() {

[Yusuke Sato, 2016/07/01 14:05:24]

Is it possible to add unit tests for this?

[malaykeshav, 2016/07/01 23:20:41]

Can be made unit testable. Just need to pass navigation_handle as argument.

+  std::string previous_url = navigation_handle()->GetReferrer().url.host();
+  std::string current_url = navigation_handle()->GetURL().host();
+  if (current_url == previous_url)

[Yusuke Sato, 2016/07/01 14:05:24]

I think this function should also return false when e.g. |previous_url| is
http://a.foo.com/ and |current_url| is http://b.foo.com/, but the current logic
does not catch such cases.

I'm not really familiar with net/ but you could probably use  SameDomainOrHost()
in net/base/registry_controlled_domains/registry_controlled_domain.h to support
that.
net/base/registry_controlled_domains/registry_controlled_domain_unittest.cc
shows how the utility function works.

[malaykeshav, 2016/07/01 23:20:41]

If we are going from mail.google.com to maps.google.com, we are not showing the
intent picker?
Done

[Yusuke Sato, 2016/07/01 23:35:56]

The original Clank code seems to properly handle such a case by comparing
handlers for mail.google.com and ones for maps.google.com (they usually differ,
which triggers the picker UI). But in our case, getting handlers for a URL
requires a slow mojo call which we don't want to use in this function...

I asked to use the net:: function because showing the UI too often is worse than
not showing it IMO.

+    return false;
+  return true;
+}
+
 }  // namespace arc