PreviewTab: Handle not viewable content

This CL handles web contents that is not viewable in the preview
tab such as those supposed to be downloaded instead. Shows a toast
message about the occasion and closes the tab.

Screenshot: https://storage.cloud.google.com/chromium-translation-screenshots/b77f7e044e4dec1b76791882126fc33e673e7f17

Bug: 981258
Change-Id: I144f953b14638901cf3846273a2c70e393066500
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2483546Reviewed-by: Donn Denman <donnd@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818785}

chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/ephemeraltab/EphemeralTabMediator.java

@@ -9,6 +9,7 @@ import android.os.Handler;
 
 import androidx.annotation.DrawableRes;
 
+import org.chromium.base.ContextUtils;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.components.browser_ui.bottomsheet.BottomSheetController;
@@ -22,6 +23,7 @@ import org.chromium.content_public.browser.NavigationHandle;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.browser.WebContentsObserver;
 import org.chromium.content_public.common.ResourceRequestBody;
+import org.chromium.ui.widget.Toast;
 import org.chromium.url.GURL;
 
 /**
@@ -125,9 +127,17 @@ public class EphemeralTabMediator {
 
             @Override
             public void didFinishNavigation(NavigationHandle navigation) {
-                if (navigation.hasCommitted() && navigation.isInMainFrame()) {
-                    mIsOnErrorPage = navigation.isErrorPage();
-                    mSheetContent.updateURL(mWebContents.get().getVisibleUrl());
+                if (navigation.isInMainFrame()) {
+                    if (navigation.hasCommitted()) {
+                        mIsOnErrorPage = navigation.isErrorPage();
+                        mSheetContent.updateURL(mWebContents.get().getVisibleUrl());
+                    } else {
+                        // Not viewable contents such as download. Show a toast and close the tab.
+                        Toast.makeText(ContextUtils.getApplicationContext(),
+                                     R.string.ephemeral_tab_sheet_not_viewable, Toast.LENGTH_SHORT)
+                                .show();
+                        mBottomSheetController.hideContent(mSheetContent, /* animate= */ true);
+                    }
                 }
             }
         };

chrome/browser/ui/android/strings/android_chrome_strings.grd

@@ -3403,6 +3403,9 @@ Data from your Incognito session will only be cleared from Chrome when you <ph n
       <message name="IDS_EPHEMERAL_TAB_SHEET_DESCRIPTION" desc="The content description of the preview tab bottom sheet.">
         Preview tab
       </message>
+      <message name="IDS_EPHEMERAL_TAB_SHEET_NOT_VIEWABLE" desc="Notifies the user that the link they are trying to preview cannot be viewed.">
+        Preview tab content is not viewable.
+      </message>
       <message name="IDS_EPHEMERAL_TAB_SHEET_OPENED_HALF" desc="Accessibility string read when the preview tab bottom sheet is opened at half height. The sheet will occupy up to half the screen.">
         Preview tab is half-opened
       </message>

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_EPHEMERAL_TAB_SHEET_NOT_VIEWABLE.png.sha1

+b77f7e044e4dec1b76791882126fc33e673e7f17
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