[ios] Fixed crash when deleting all saved password

Bug: 898678

Change-Id: Ib1fe23936b6d6196e760a50559b0895c7aaa4a0f
Reviewed-on: https://chromium-review.googlesource.com/c/1301453
Commit-Queue: David Jean <djean@chromium.org>
Reviewed-by: Peter Lee <pkl@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603441}

ios/chrome/browser/ui/settings/passwords_settings_egtest.mm

@@ -1643,6 +1643,41 @@ PasswordForm CreateSampleFormWithIndex(int index) {
       assertWithMatcher:grey_notNil()];
 }
 
+// Test search and delete all passwords and blacklisted items.
+- (void)testSearchAndDeleteAllPasswords {
+  SaveExamplePasswordForms();
+  SaveExampleBlacklistedForms();
+
+  OpenPasswordSettings();
+
+  [[EarlGrey selectElementWithMatcher:SearchTextField()]
+      performAction:grey_typeText(@"u\n")];
+
+  TapEdit();
+
+  // Select all.
+  [GetInteractionForPasswordEntry(@"example11.com, user1")
+      performAction:grey_tap()];
+  [GetInteractionForPasswordEntry(@"example12.com, user2")
+      performAction:grey_tap()];
+  [GetInteractionForPasswordEntry(@"exclude1.com") performAction:grey_tap()];
+  [GetInteractionForPasswordEntry(@"exclude2.com") performAction:grey_tap()];
+
+  // Delete them.
+  [[EarlGrey selectElementWithMatcher:DeleteButtonAtBottom()]
+      performAction:grey_tap()];
+
+  // All should be gone.
+  [GetInteractionForPasswordEntry(@"example11.com, user1")
+      assertWithMatcher:grey_nil()];
+  [GetInteractionForPasswordEntry(@"example12.com, user2")
+      assertWithMatcher:grey_nil()];
+  [GetInteractionForPasswordEntry(@"exclude1.com")
+      assertWithMatcher:grey_nil()];
+  [GetInteractionForPasswordEntry(@"exclude2.com")
+      assertWithMatcher:grey_nil()];
+}
+
 // Test that user can't search passwords while in edit mode.
 - (void)testCantSearchPasswordsWhileInEditMode {
   SaveExamplePasswordForms();

ios/chrome/browser/ui/settings/save_passwords_collection_view_controller.mm

@@ -830,11 +830,14 @@ blacklistedFormItemWithText:(NSString*)text
     SavePasswordsCollectionViewController* strongSelf = weakSelf;
     if (!strongSelf)
       return;
-    [strongSelf clearSectionWithIdentifier:SectionIdentifierSavedPasswords
-                                   ifEmpty:strongSelf->savedForms_.empty()];
+    // Delete in reverse order of section indexes (bottom up of section
+    // displayed), so that indexes in model matches those in the view.  if we
+    // don't we'll cause a crash.
     [strongSelf
         clearSectionWithIdentifier:SectionIdentifierBlacklist
                            ifEmpty:strongSelf->blacklistedForms_.empty()];
+    [strongSelf clearSectionWithIdentifier:SectionIdentifierSavedPasswords
+                                   ifEmpty:strongSelf->savedForms_.empty()];
     [strongSelf
         clearSectionWithIdentifier:SectionIdentifierSearchPasswordsBox
                            ifEmpty:strongSelf->savedForms_.empty() &&