[Document mode] Keep tab ID list in sync with Tab entries

It is possible to have one DocumentActivity create a Tab and add its ID to the
DocumentTabModel, but get interrupted (somehow) before the Tab Entry is added
to the DocumentTabModel.  This results in getCount() returning the correct number
of Tabs that exist but fail to have any information about the new Tab, resulting
in getTabAt() returning |null|.  We should instead keep the ID list and the Entry
list be as in sync as possible, adding the Entry directly to the DocumentTabModel
as soon as we let the DocumentTabModel know about the Tab's existence.

Add new methods to tie the addTabId and updateEntry functions together via addTab,
deprecate the old ones, and assert that we should never get into a bad state.
Deprecated methods will be culled when the downstream patch lands.

BUG=457427
Original commit: https://crrev.com/7710ef5ff57f581f66dbbaad2dffe8c4a9048add
Original review: https://codereview.chromium.org/969443003

TBR=mariakhomenko@chromium.org

Review URL: https://codereview.chromium.org/973123002

Cr-Commit-Position: refs/branch-heads/2311@{#101}
Cr-Branched-From: 09b7de5dd7254947cd4306de907274fa63373d48-refs/heads/master@{#317474}

3 files changed, 24 insertions, 2 deletions

diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModel.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModel.java
index 85f58b6..ff7e1e6 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModel.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModel.java
@@ -168,6 +168,13 @@ public interface DocumentTabModel extends TabModel {
     void addTab(Tab tab);
 
     /**
+     * Adds the given Tab to this TabModel.
+     * @param intent Intent of the DocumentActivity.
+     * @param tab Tab to add.
+     */
+    void addTab(Intent intent, Tab tab);
+
+    /**
      * @return The stage of initialization that the DocumentTabModel is currently going through.
      */
     int getCurrentInitializationStage();
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModelImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModelImpl.java
index 2eda870..1d70e46 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModelImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/DocumentTabModelImpl.java
@@ -266,7 +266,7 @@ public class DocumentTabModelImpl extends TabModelJniBridge implements DocumentT
 
         // Try to create a Tab that will hold the Tab's info.
         Entry entry = mEntryMap.get(tabId);
-        if (entry == null) return null;
+        assert entry != null;
 
         // If a tab has already been initialized, use that.
         if (entry.placeholderTab != null && entry.placeholderTab.isInitialized()) {
@@ -351,6 +351,7 @@ public class DocumentTabModelImpl extends TabModelJniBridge implements DocumentT
      * @param tabId ID to add.
      */
     private void addTabId(int index, int tabId) {
+        assert tabId != Tab.INVALID_TAB_ID;
         if (mTabIdList.contains(tabId)) return;
         mTabIdList.add(index, tabId);
     }
@@ -430,7 +431,7 @@ public class DocumentTabModelImpl extends TabModelJniBridge implements DocumentT
 
     @Override
     public void updateEntry(Intent intent, Tab tab) {
-        if (!mActivityDelegate.isValidActivity(isIncognito(), intent)) return;
+        assert mActivityDelegate.isValidActivity(isIncognito(), intent);
 
         int id = ActivityDelegate.getTabIdFromIntent(intent);
         if (id == Tab.INVALID_TAB_ID) return;
@@ -870,6 +871,14 @@ public class DocumentTabModelImpl extends TabModelJniBridge implements DocumentT
     }
 
     @Override
+    public void addTab(Intent intent, Tab tab) {
+        int parentIndex = indexOf(tab.getParentId());
+        int index = parentIndex == -1 ? getCount() : parentIndex + 1;
+        addTab(tab, index, tab.getLaunchType());
+        updateEntry(intent, tab);
+    }
+
+    @Override
     public void addTab(Tab tab, int index, TabLaunchType type) {
         for (TabModelObserver obs : mObservers) obs.willAddTab(tab, type);
 
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/OffTheRecordDocumentTabModel.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/OffTheRecordDocumentTabModel.java
index ab51905..a85fc7e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/OffTheRecordDocumentTabModel.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/document/OffTheRecordDocumentTabModel.java
@@ -114,6 +114,12 @@ public class OffTheRecordDocumentTabModel extends OffTheRecordTabModel implement
     }
 
     @Override
+    public void addTab(Intent intent, Tab tab) {
+        ensureTabModelImpl();
+        getDelegateDocumentTabModel().addTab(intent, tab);
+    }
+
+    @Override
     public boolean closeTabAt(int index) {
         boolean success = false;
         if (isDocumentTabModelImplCreated()) {