[Fuchsia] Fix FrameImpl to cope with multiple View lifetimes.

Tear-down any existing View-related resources (e.g. Aura window, focus
controller etc) if a CreateView() request is received while a View is
already active for this Frame.

Bug: 920490
Change-Id: Iec4f7d393e33d583bc7dc8caf0bbea5f4ae11f6d
Reviewed-on: https://chromium-review.googlesource.com/c/1423901
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628554}

fuchsia/browser/frame_impl.h

@@ -50,6 +50,7 @@ class FrameImpl : public chromium::web::Frame,
   zx::unowned_channel GetBindingChannelForTest() const;
 
   content::WebContents* web_contents_for_test() { return web_contents_.get(); }
+  bool has_view_for_test() { return window_tree_host_ != nullptr; }
 
   // chromium::web::Frame implementation.
   void CreateView(
@@ -96,6 +97,15 @@ class FrameImpl : public chromium::web::Frame,
     DISALLOW_COPY_AND_ASSIGN(OriginScopedScript);
   };
 
+  aura::Window* root_window() const { return window_tree_host_->window(); }
+
+  // Release the resources associated with the View, if one is active.
+  void TearDownView();
+
+  // Sends |pending_navigation_event_| to the observer if there are any changes
+  // to be reported.
+  void MaybeSendNavigationEvent();
+
   // chromium::web::NavigationController implementation.
   void LoadUrl(std::string url,
                std::unique_ptr<chromium::web::LoadUrlParams> params) override;
@@ -105,12 +115,6 @@ class FrameImpl : public chromium::web::Frame,
   void Reload(chromium::web::ReloadType type) override;
   void GetVisibleEntry(GetVisibleEntryCallback callback) override;
 
-  aura::Window* root_window() const { return window_tree_host_->window(); }
-
-  // Sends |pending_navigation_event_| to the observer if there are any changes
-  // to be reported.
-  void MaybeSendNavigationEvent();
-
   // content::WebContentsDelegate implementation.
   bool ShouldCreateWebContents(
       content::WebContents* web_contents,

fuchsia/browser/frame_impl_browsertest.cc

@@ -978,6 +978,46 @@ IN_PROC_BROWSER_TEST_F(FrameImplTest, PostMessageBadOriginDropped) {
   EXPECT_FALSE(unused_message_read.has_value());
 }
 
+IN_PROC_BROWSER_TEST_F(FrameImplTest, RecreateView) {
+  chromium::web::FramePtr frame = CreateFrame();
+
+  ASSERT_TRUE(embedded_test_server()->Start());
+
+  // Process the Frame creation request, and verify we can get the FrameImpl.
+  base::RunLoop().RunUntilIdle();
+  FrameImpl* frame_impl = context_impl()->GetFrameImplForTest(&frame);
+  ASSERT_TRUE(frame_impl);
+  EXPECT_FALSE(frame_impl->has_view_for_test());
+
+  chromium::web::NavigationControllerPtr controller;
+  frame->GetNavigationController(controller.NewRequest());
+
+  // Verify that the Frame can navigate, prior to the View being created.
+  const GURL page1_url(embedded_test_server()->GetURL(kPage1Path));
+  CheckLoadUrl(page1_url.spec(), kPage1Title, nullptr, controller.get());
+
+  // Request a View from the Frame, and pump the loop to process the request.
+  zx::eventpair owner_token, frame_token;
+  ASSERT_EQ(zx::eventpair::create(0, &owner_token, &frame_token), ZX_OK);
+  frame->CreateView2(std::move(frame_token), nullptr, nullptr);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(frame_impl->has_view_for_test());
+
+  // Verify that the Frame still works, by navigating to Page #2.
+  const GURL page2_url(embedded_test_server()->GetURL(kPage2Path));
+  CheckLoadUrl(page2_url.spec(), kPage2Title, nullptr, controller.get());
+
+  // Create new View tokens and request a new view.
+  zx::eventpair owner_token2, frame_token2;
+  ASSERT_EQ(zx::eventpair::create(0, &owner_token2, &frame_token2), ZX_OK);
+  frame->CreateView2(std::move(frame_token), nullptr, nullptr);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(frame_impl->has_view_for_test());
+
+  // Verify that the Frame still works, by navigating back to Page #1.
+  CheckLoadUrl(page1_url.spec(), kPage1Title, nullptr, controller.get());
+}
+
 class RequestMonitoringFrameImplBrowserTest : public FrameImplTest {
  public:
   RequestMonitoringFrameImplBrowserTest() = default;