If a dialog is shown, drop fullscreen.

BUG=875066, 817809, 792876, 812769, 813815
TEST=included

Change-Id: Ic3d697fa3c4b01f5d7fea77391857177ada660db
Reviewed-on: https://chromium-review.googlesource.com/1185208Reviewed-by: Sidney San Martín <sdy@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586418}

chrome/browser/ui/browser.cc

@@ -2052,6 +2052,13 @@ void Browser::SetWebContentsBlocked(content::WebContents* web_contents,
     // TabStripModel.
     return;
   }
+
+  // For security, if the WebContents is in fullscreen, have it drop fullscreen.
+  // This gives the user the context they need in order to make informed
+  // decisions.
+  if (web_contents->IsFullscreenForCurrentTab())
+    web_contents->ExitFullscreen(true);
+
   tab_strip_model_->SetTabBlocked(index, blocked);
 
   bool browser_active = BrowserList::GetInstance()->GetLastActive() == this;

chrome/browser/ui/browser_browsertest.cc

@@ -2747,3 +2747,26 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, TestPopupBounds) {
     browser->window()->Close();
   }
 }
+
+// Makes sure showing dialogs drops fullscreen.
+IN_PROC_BROWSER_TEST_F(BrowserTest, DialogsDropFullscreen) {
+  WebContents* tab = browser()->tab_strip_model()->GetActiveWebContents();
+
+  content::WebContentsDelegate* browser_as_wc_delegate =
+      static_cast<content::WebContentsDelegate*>(browser());
+  web_modal::WebContentsModalDialogManagerDelegate* browser_as_dialog_delegate =
+      static_cast<web_modal::WebContentsModalDialogManagerDelegate*>(browser());
+
+  // Simulate the tab requesting fullscreen.
+  browser_as_wc_delegate->EnterFullscreenModeForTab(
+      tab, GURL(), blink::WebFullscreenOptions());
+  EXPECT_TRUE(browser_as_wc_delegate->IsFullscreenForTabOrPending(tab));
+
+  // The tab gets a modal dialog.
+  browser_as_dialog_delegate->SetWebContentsBlocked(tab, true);
+
+  // The dialog should drop fullscreen.
+  EXPECT_FALSE(browser_as_wc_delegate->IsFullscreenForTabOrPending(tab));
+
+  browser_as_dialog_delegate->SetWebContentsBlocked(tab, false);
+}

content/browser/web_contents/web_contents_impl.cc

@@ -5180,6 +5180,10 @@ void WebContentsImpl::RunBeforeUnloadConfirm(
 
 void WebContentsImpl::RunFileChooser(RenderFrameHost* render_frame_host,
                                      const FileChooserParams& params) {
+  // Any explicit focusing of another window while this WebContents is in
+  // fullscreen can be used to confuse the user, so drop fullscreen.
+  ForSecurityDropFullscreen();
+
   if (delegate_)
     delegate_->RunFileChooser(render_frame_host, params);
 }

content/browser/web_contents/web_contents_impl.h

@@ -1024,6 +1024,8 @@ class CONTENT_EXPORT WebContentsImpl : public WebContents,
                            DialogsFromJavaScriptEndFullscreen);
   FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,
                            DialogsFromJavaScriptEndFullscreenEvenInInnerWC);
+  FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,
+                           FileChooserEndsFullscreen);
   FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,
                            PopupsFromJavaScriptEndFullscreen);
   FRIEND_TEST_ALL_PREFIXES(WebContentsImplBrowserTest,

content/browser/web_contents/web_contents_impl_browsertest.cc

@@ -2190,6 +2190,23 @@ IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest,
   top_contents->SetJavaScriptDialogManagerForTesting(nullptr);
 }
 
+IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest, FileChooserEndsFullscreen) {
+  WebContentsImpl* wc = static_cast<WebContentsImpl*>(shell()->web_contents());
+  TestWCDelegateForDialogsAndFullscreen test_delegate;
+  wc->SetDelegate(&test_delegate);
+
+  GURL url("about:blank");
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  wc->EnterFullscreenMode(url, blink::WebFullscreenOptions());
+  EXPECT_TRUE(wc->IsFullscreenForCurrentTab());
+  wc->RunFileChooser(wc->GetMainFrame(), FileChooserParams());
+  EXPECT_FALSE(wc->IsFullscreenForCurrentTab());
+
+  wc->SetDelegate(nullptr);
+  wc->SetJavaScriptDialogManagerForTesting(nullptr);
+}
+
 IN_PROC_BROWSER_TEST_F(WebContentsImplBrowserTest,
                        PopupsFromJavaScriptEndFullscreen) {
   WebContentsImpl* wc = static_cast<WebContentsImpl*>(shell()->web_contents());