[Payment Request][Android] Attach UI right before blocking interactions

Before this patch, if PaymentRequest.show() was called in a CCT, then
user opened the CCT page in Chrome, and a skip-UI payment app was slow
to respond to the `canmakepayment` event, then the activity to which
Chrome attached the payment UI would be gone by the time the payment UI
needs to be shown, which would cause a crash. The skip-UI bit is
important, because in this flow Chrome blocks UI interactions only after
launching the payment app (after the response to `canmakepayment`
event).

This patch waits to attach the payment UI to the current Chrome activity
via buildUI(chromeActivity) until immediately before blocking UI
interactions via mUI.show() or mUI.dimBackground().

After this patch, Chrome does not crash when PaymentRequest.show() was
called in a CCT for skip-UI flow and the user opened the CCT page in
Chrome before the payment app responded to the `canmakepayment` event.

Bug: 817073
Change-Id: I5ce50d000c2f64a60c62955d9e3e8f080498238d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1506494
Commit-Queue: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Danyao Wang <danyao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638617}

chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java

@@ -4,7 +4,6 @@
 
 package org.chromium.chrome.browser.payments;
 
-import android.app.Activity;
 import android.content.Context;
 import android.os.Handler;
 import android.support.annotation.Nullable;
@@ -485,9 +484,38 @@ public class PaymentRequestImpl
                 && mMethodData.keySet().iterator().next().startsWith(UrlConstants.HTTPS_URL_PREFIX);
     }
 
-    private void buildUI(Activity activity) {
+    /** @return Whether the UI was built. */
+    private boolean buildUI(ChromeActivity activity) {
         assert activity != null;
 
+        // Catch any time the user switches tabs. Because the dialog is modal, a user shouldn't be
+        // allowed to switch tabs, which can happen if the user receives an external Intent.
+        mObservedTabModelSelector = activity.getTabModelSelector();
+        mObservedTabModel = activity.getCurrentTabModel();
+        mObservedTabModelSelector.addObserver(mSelectorObserver);
+        mObservedTabModel.addObserver(mTabModelObserver);
+
+        // Only the currently selected tab is allowed to show the payment UI.
+        if (TabModelUtils.getCurrentWebContents(mObservedTabModel) != mWebContents) {
+            mJourneyLogger.setNotShown(NotShownReason.OTHER);
+            disconnectFromClientWithDebugMessage(
+                    "Background tab is not allowed to show PaymentRequest UI");
+            if (sObserverForTest != null) sObserverForTest.onPaymentRequestServiceShowFailed();
+            return false;
+        }
+
+        // Catch any time the user enters the overview mode and dismiss the payment UI.
+        if (activity instanceof ChromeTabbedActivity) {
+            mOverviewModeBehavior = ((ChromeTabbedActivity) activity).getOverviewModeBehavior();
+            if (mOverviewModeBehavior.overviewVisible()) {
+                mJourneyLogger.setNotShown(NotShownReason.OTHER);
+                disconnectFromClientWithDebugMessage("In tab overview mode");
+                if (sObserverForTest != null) sObserverForTest.onPaymentRequestServiceShowFailed();
+                return false;
+            }
+            mOverviewModeBehavior.addOverviewModeObserver(mOverviewModeObserver);
+        }
+
         List<AutofillProfile> profiles = null;
         if (mRequestShipping || mRequestPayerName || mRequestPayerPhone || mRequestPayerEmail) {
             profiles = PersonalDataManager.getInstance().getProfilesToSuggest(
@@ -531,6 +559,8 @@ public class PaymentRequestImpl
         mAddressEditor.setEditorDialog(mUI.getEditorDialog());
         mCardEditor.setEditorDialog(mUI.getCardEditorDialog());
         if (mContactEditor != null) mContactEditor.setEditorDialog(mUI.getEditorDialog());
+
+        return true;
     }
 
     private void createShippingSection(
@@ -622,43 +652,16 @@ public class PaymentRequestImpl
             return;
         }
 
-        // Catch any time the user switches tabs. Because the dialog is modal, a user shouldn't be
-        // allowed to switch tabs, which can happen if the user receives an external Intent.
-        mObservedTabModelSelector = chromeActivity.getTabModelSelector();
-        mObservedTabModel = chromeActivity.getCurrentTabModel();
-        mObservedTabModelSelector.addObserver(mSelectorObserver);
-        mObservedTabModel.addObserver(mTabModelObserver);
-
-        // Only the currently selected tab is allowed to show the payment UI.
-        if (TabModelUtils.getCurrentWebContents(mObservedTabModel) != mWebContents) {
-            mJourneyLogger.setNotShown(NotShownReason.OTHER);
-            disconnectFromClientWithDebugMessage(
-                    "Background tab is not allowed to show PaymentRequest UI");
-            if (sObserverForTest != null) sObserverForTest.onPaymentRequestServiceShowFailed();
-            return;
-        }
-
-        // Catch any time the user enters the overview mode and dismiss the payment UI.
-        if (chromeActivity instanceof ChromeTabbedActivity) {
-            mOverviewModeBehavior =
-                    ((ChromeTabbedActivity) chromeActivity).getOverviewModeBehavior();
-            if (mOverviewModeBehavior.overviewVisible()) {
-                mJourneyLogger.setNotShown(NotShownReason.OTHER);
-                disconnectFromClientWithDebugMessage("In tab overview mode");
-                if (sObserverForTest != null) sObserverForTest.onPaymentRequestServiceShowFailed();
-                return;
-            }
-            mOverviewModeBehavior.addOverviewModeObserver(mOverviewModeObserver);
-        }
-
         mIsUserGestureShow = isUserGesture;
-        buildUI(chromeActivity);
-        if (!mShouldSkipShowingPaymentRequestUi) mUI.show();
+        if (!mShouldSkipShowingPaymentRequestUi) {
+            if (!buildUI(chromeActivity)) return;
+            mUI.show();
+        }
 
-        triggerPaymentAppUiSkipIfApplicable();
+        triggerPaymentAppUiSkipIfApplicable(chromeActivity);
     }
 
-    private void triggerPaymentAppUiSkipIfApplicable() {
+    private void triggerPaymentAppUiSkipIfApplicable(ChromeActivity chromeActivity) {
         // If we are skipping showing the Payment Request UI, we should call into the
         // PaymentApp immediately after we determine the instruments are ready and UI is shown.
         if (mShouldSkipShowingPaymentRequestUi && isFinishedQueryingPaymentApps()
@@ -667,6 +670,7 @@ public class PaymentRequestImpl
 
             PaymentInstrument selectedInstrument =
                     (PaymentInstrument) mPaymentMethodsSection.getSelectedItem();
+            if (!buildUI(chromeActivity)) return;
 
             // Do not skip to payment app if it is not the only one, it's not pre-selected, or if
             // skip-UI requires a user gesture in show(), which was not present.
@@ -1829,15 +1833,20 @@ public class PaymentRequestImpl
             respondHasEnrolledInstrumentQuery(mHasEnrolledInstrument);
         }
 
+        ChromeActivity chromeActivity = ChromeActivity.fromWebContents(mWebContents);
+        if (chromeActivity == null) {
+            mJourneyLogger.setNotShown(NotShownReason.OTHER);
+            disconnectFromClientWithDebugMessage("Unable to find Chrome activity");
+            if (sObserverForTest != null) sObserverForTest.onPaymentRequestServiceShowFailed();
+            return;
+        }
+
         // The list of payment instruments is ready to display.
         mPaymentMethodsSection = new SectionInformation(PaymentRequestUI.DataType.PAYMENT_METHODS,
                 selection, new ArrayList<>(mPendingInstruments));
         if (mPaymentMethodsSectionAdditionalTextResourceId != 0) {
-            Context context = ChromeActivity.fromWebContents(mWebContents);
-            if (context != null) {
-                mPaymentMethodsSection.setAdditionalText(
-                        context.getString(mPaymentMethodsSectionAdditionalTextResourceId));
-            }
+            mPaymentMethodsSection.setAdditionalText(
+                    chromeActivity.getString(mPaymentMethodsSectionAdditionalTextResourceId));
         }
 
         // Record the number suggested payment methods and whether at least one of them was
@@ -1855,7 +1864,7 @@ public class PaymentRequestImpl
 
         SettingsAutofillAndPaymentsObserver.getInstance().registerObserver(this);
 
-        triggerPaymentAppUiSkipIfApplicable();
+        triggerPaymentAppUiSkipIfApplicable(chromeActivity);
     }
 
     /**