PreviewTab: Allow permission dialog

Permission UI requires a ModalDialogaManager from the associated
WindowAndroid instance, which was not available on Preview Tab.
This CL overrides |ActivityWindowAndroid.getModalDialogManager|
passed to the ThinWebView object of Preview Tab so that the
permission UI can be displayed.

Verified on a local device that this fixes the reported crash,
and shows the permission UI as expected.

Bug: 1057951
Change-Id: Ic7745d40edbea466ab1fef2de176743c3fda675d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094386Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749043}

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

@@ -24,6 +24,7 @@ import org.chromium.chrome.browser.thinwebview.ThinWebViewConstraints;
 import org.chromium.chrome.browser.thinwebview.ThinWebViewFactory;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheetContent;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheetController;
+import org.chromium.components.browser_ui.modaldialog.AppModalPresenter;
 import org.chromium.components.browser_ui.widget.FadingShadow;
 import org.chromium.components.browser_ui.widget.FadingShadowView;
 import org.chromium.components.embedder_support.delegate.WebContentsDelegateAndroid;
@@ -33,6 +34,7 @@ import org.chromium.components.url_formatter.UrlFormatter;
 import org.chromium.content_public.browser.RenderCoordinates;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.ui.base.ActivityWindowAndroid;
+import org.chromium.ui.modaldialog.ModalDialogManager;
 import org.chromium.url.GURL;
 
 /**
@@ -56,6 +58,7 @@ public class EphemeralTabSheetContent implements BottomSheetContent {
     private FadingShadowView mShadow;
     private Drawable mCurrentFavicon;
     private ImageView mFaviconView;
+    private ModalDialogManager mModalDialogManager;
 
     /**
      * Constructor.
@@ -99,8 +102,12 @@ public class EphemeralTabSheetContent implements BottomSheetContent {
      * bottom sheet.
      */
     private void createThinWebView(int maxSheetHeight) {
-        mThinWebView = ThinWebViewFactory.create(
-                mContext, new ActivityWindowAndroid(mContext), new ThinWebViewConstraints());
+        mThinWebView = ThinWebViewFactory.create(mContext, new ActivityWindowAndroid(mContext) {
+            @Override
+            public @Nullable ModalDialogManager getModalDialogManager() {
+                return EphemeralTabSheetContent.this.getModalDialogManager();
+            }
+        }, new ThinWebViewConstraints());
 
         mSheetContentView = new FrameLayout(mContext);
         mThinWebView.getView().setLayoutParams(new FrameLayout.LayoutParams(
@@ -110,6 +117,14 @@ public class EphemeralTabSheetContent implements BottomSheetContent {
         mSheetContentView.setPadding(0, mToolbarHeightPx, 0, 0);
     }
 
+    private ModalDialogManager getModalDialogManager() {
+        if (mModalDialogManager == null) {
+            mModalDialogManager = new ModalDialogManager(
+                    new AppModalPresenter(mContext), ModalDialogManager.ModalDialogType.APP);
+        }
+        return mModalDialogManager;
+    }
+
     private void createToolbarView() {
         mToolbarView =
                 (ViewGroup) LayoutInflater.from(mContext).inflate(R.layout.sheet_tab_toolbar, null);
@@ -231,6 +246,10 @@ public class EphemeralTabSheetContent implements BottomSheetContent {
     @Override
     public void destroy() {
         mThinWebView.destroy();
+        if (mModalDialogManager != null) {
+            mModalDialogManager.destroy();
+            mModalDialogManager = null;
+        }
     }
 
     @Override