Add the ability to override WebContentsBindingSet binders for testing

content/browser/web_contents_binding_set_browsertest.cc

+// Copyright 2017 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 "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/public/browser/web_contents_binding_set.h"
+#include "content/public/test/browser_test_utils.h"
+#include "content/public/test/content_browser_test.h"
+#include "content/public/test/content_browser_test_utils.h"
+#include "content/shell/browser/shell.h"
+#include "content/test/test_browser_associated_interfaces.mojom.h"
+
+namespace content {
+
+using WebContentsBindingSetBrowserTest = ContentBrowserTest;
+
+namespace {
+
+class TestInterfaceBinder : public WebContentsBindingSet::TestBinder<
+                                mojom::BrowserAssociatedInterfaceTestDriver> {
+ public:
+  explicit TestInterfaceBinder(const base::Closure& bind_callback)
+      : bind_callback_(bind_callback) {}
+  ~TestInterfaceBinder() override {}
+
+  void BindRequest(RenderFrameHost* frame_host,
+                   mojom::BrowserAssociatedInterfaceTestDriverAssociatedRequest
+                       request) override {
+    bind_callback_.Run();
+  }
+
+ private:
+  const base::Closure bind_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestInterfaceBinder);
+};
+
+}  // namespace
+
+IN_PROC_BROWSER_TEST_F(WebContentsBindingSetBrowserTest, OverrideForTesting) {
+  NavigateToURL(shell(), GURL("data:text/html,ho hum"));
+
+  // Ensure that we can add a WebContentsFrameBindingSet and then override its
+  // request handler.
+  auto* web_contents = static_cast<WebContentsImpl*>(shell()->web_contents());
+  WebContentsFrameBindingSet<mojom::BrowserAssociatedInterfaceTestDriver>
+      frame_bindings(web_contents, nullptr);
+
+  // Now override the binder for this interface. It quits |run_loop| whenever
+  // an incoming interface request is received.
+  base::RunLoop run_loop;
+  web_contents
+      ->OverrideBinderForTesting<mojom::BrowserAssociatedInterfaceTestDriver>(
+          base::MakeUnique<TestInterfaceBinder>(run_loop.QuitClosure()));
+
+  // Simulate an inbound request for the test interface. This should get routed
+  // to the overriding binder and allow the test to complete.
+  mojom::BrowserAssociatedInterfaceTestDriverAssociatedPtr override_client;
+  web_contents->OnAssociatedInterfaceRequest(
+      web_contents->GetMainFrame(),
+      mojom::BrowserAssociatedInterfaceTestDriver::Name_,
+      mojo::GetIsolatedProxy(&override_client).PassHandle());
+  run_loop.Run();
+}
+
+}  // namespace content