Filters out URL clicks based on host matching only.

chrome/browser/chromeos/arc/arc_navigation_throttle.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/arc/arc_navigation_throttle.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 47 matching lines @@
       weak_ptr_factory_(this) {}
 
 ArcNavigationThrottle::~ArcNavigationThrottle() = default;
 
 content::NavigationThrottle::ThrottleCheckResult
 ArcNavigationThrottle::WillStartRequest() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   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)
     return content::NavigationThrottle::PROCEED;
   bridge_instance->RequestUrlHandlerList(
       url.spec(), base::Bind(&ArcNavigationThrottle::OnAppCandidatesReceived,
                              weak_ptr_factory_.GetWeakPtr()));
   return content::NavigationThrottle::DEFER;
 }
 
@@ skipping 122 matching lines @@
       NOTREACHED();
       return;
     }
   }
 
   UMA_HISTOGRAM_ENUMERATION("Arc.IntentHandlerAction",
                             static_cast<int>(close_reason),
                             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