Security drop fullscreen for any nested WebContents level.

BUG=873080
TEST=as in bug

Change-Id: Icd75715ac42789c84870967b11c9917a972ae086
Reviewed-on: https://chromium-review.googlesource.com/1173342
Commit-Queue: Avi Drissman <avi@chromium.org>
Reviewed-by: Sidney San Martín <sdy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582970}

content/browser/web_contents/web_contents_impl.cc

@@ -2695,8 +2695,7 @@ void WebContentsImpl::CreateNewWindow(
 
   // Any new WebContents opened while this WebContents is in fullscreen can be
   // used to confuse the user, so drop fullscreen.
-  if (IsFullscreenForCurrentTab())
-    ExitFullscreen(true);
+  ForSecurityDropFullscreen();
 
   if (params.opener_suppressed) {
     // When the opener is suppressed, the original renderer cannot access the
@@ -4366,8 +4365,7 @@ void WebContentsImpl::ViewSource(RenderFrameHostImpl* frame) {
 
   // Any new WebContents opened while this WebContents is in fullscreen can be
   // used to confuse the user, so drop fullscreen.
-  if (IsFullscreenForCurrentTab())
-    ExitFullscreen(true);
+  ForSecurityDropFullscreen();
 
   // We intentionally don't share the SiteInstance with the original frame so
   // that view source has a consistent process model and always ends up in a new
@@ -5078,8 +5076,7 @@ void WebContentsImpl::RunJavaScriptDialog(RenderFrameHost* render_frame_host,
 
   // Running a dialog causes an exit to webpage-initiated fullscreen.
   // http://crbug.com/728276
-  if (IsFullscreenForCurrentTab())
-    ExitFullscreen(true);
+  ForSecurityDropFullscreen();
 
   auto callback =
       base::BindOnce(&WebContentsImpl::OnDialogClosed, base::Unretained(this),
@@ -5148,8 +5145,7 @@ void WebContentsImpl::RunBeforeUnloadConfirm(
 
   // Running a dialog causes an exit to webpage-initiated fullscreen.
   // http://crbug.com/728276
-  if (IsFullscreenForCurrentTab())
-    ExitFullscreen(true);
+  ForSecurityDropFullscreen();
 
   RenderFrameHostImpl* rfhi =
       static_cast<RenderFrameHostImpl*>(render_frame_host);
@@ -5731,6 +5727,15 @@ void WebContentsImpl::EnsureOpenerProxiesExist(RenderFrameHost* source_rfh) {
   }
 }
 
+void WebContentsImpl::ForSecurityDropFullscreen() {
+  WebContentsImpl* web_contents = this;
+  while (web_contents) {
+    if (web_contents->IsFullscreenForCurrentTab())
+      web_contents->ExitFullscreen(true);
+    web_contents = web_contents->GetOuterWebContents();
+  }
+}
+
 void WebContentsImpl::SetAsFocusedWebContentsIfNecessary() {
   // Only change focus if we are not currently focused.
   WebContentsImpl* old_contents = GetFocusedWebContents();
@@ -5798,8 +5803,7 @@ void WebContentsImpl::SetFocusedFrame(FrameTreeNode* node,
 void WebContentsImpl::DidCallFocus() {
   // Any explicit focusing of another window while this WebContents is in
   // fullscreen can be used to confuse the user, so drop fullscreen.
-  if (IsFullscreenForCurrentTab())
-    ExitFullscreen(true);
+  ForSecurityDropFullscreen();
 }
 
 RenderFrameHost* WebContentsImpl::GetFocusedFrameIncludingInnerWebContents() {

content/browser/web_contents/web_contents_impl.h

@@ -926,6 +926,11 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
   // |IsFullscreen| must return |true| when this method is called.
   bool IsPictureInPictureAllowedForFullscreenVideo() const;
 
+  // The WebContents is trying to take some action that would cause user
+  // confusion if taken while in fullscreen. If this WebContents or any outer
+  // WebContents is in fullscreen, drop it.
+  void ForSecurityDropFullscreen();
+
   // When inner or outer WebContents are present, become the focused
   // WebContentsImpl. This will activate this content's main frame RenderWidget
   // and indirectly all its subframe widgets.  GetFocusedRenderWidgetHost will
@@ -1016,6 +1021,8 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
                            JavaScriptDialogsInMainAndSubframes);
   FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,
                            DialogsFromJavaScriptEndFullscreen);
+  FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,
+                           DialogsFromJavaScriptEndFullscreenEvenInInnerWC);
   FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,
                            PopupsFromJavaScriptEndFullscreen);
   FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,

content/browser/web_contents/web_contents_impl_browsertest.cc

@@ -2132,6 +2132,51 @@ IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest,
   wc->SetJavaScriptDialogManagerForTesting(nullptr);
 }
 
+IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest,
+                       DialogsFromJavaScriptEndFullscreenEvenInInnerWC) {
+  WebContentsImpl* top_contents =
+      static_cast<WebContentsImpl*>(shell()->web_contents());
+  TestWCDelegateForDialogsAndFullscreen top_test_delegate;
+  top_contents->SetDelegate(&top_test_delegate);
+
+  GURL url("about:blank");
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  FrameTreeNode* root = top_contents->GetFrameTree()->root();
+  ASSERT_EQ(0U, root->child_count());
+
+  std::string script =
+      "var iframe = document.createElement('iframe');"
+      "document.body.appendChild(iframe);";
+  EXPECT_TRUE(content::ExecuteScript(root->current_frame_host(), script));
+  EXPECT_TRUE(WaitForLoadStop(shell()->web_contents()));
+
+  ASSERT_EQ(1U, root->child_count());
+  RenderFrameHost* frame = root->child_at(0)->current_frame_host();
+  ASSERT_NE(nullptr, frame);
+
+  WebContentsImpl* inner_contents =
+      static_cast<WebContentsImpl*>(CreateAndAttachInnerContents(frame));
+  TestWCDelegateForDialogsAndFullscreen inner_test_delegate;
+  inner_contents->SetDelegate(&inner_test_delegate);
+
+  // A dialog from the inner WebContents should make the outer contents lose
+  // fullscreen.
+  top_contents->EnterFullscreenMode(url, blink::WebFullscreenOptions());
+  EXPECT_TRUE(top_contents->IsFullscreenForCurrentTab());
+  script = "alert('hi')";
+  inner_test_delegate.WillWaitForDialog();
+  EXPECT_TRUE(content::ExecuteScript(inner_contents, script));
+  inner_test_delegate.Wait();
+  EXPECT_FALSE(top_contents->IsFullscreenForCurrentTab());
+
+  inner_contents->SetDelegate(nullptr);
+  inner_contents->SetJavaScriptDialogManagerForTesting(nullptr);
+
+  top_contents->SetDelegate(nullptr);
+  top_contents->SetJavaScriptDialogManagerForTesting(nullptr);
+}
+
 IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest,
                        PopupsFromJavaScriptEndFullscreen) {
   WebContentsImpl* wc = static_cast<WebContentsImpl*>(shell()->web_contents());