Bug 1331154 - 5. Notify browser.js when a tab gets moved. r=sebastian

Session store will be notified in the next patch.

MozReview-Commit-ID: APTJykdnMF2

--HG--
extra : rebase_source : f3cdd3e5529f470834c32d6ae2289a6d272cba67

mobile/android/base/java/org/mozilla/gecko/Tabs.java

@@ -1137,8 +1137,10 @@ public class Tabs implements BundleEventListener {
         // but we need the indices with respect to mOrder, which lists all tabs, both private and
         // non-private, in the order in which they were added.
 
+        // The positions in mOrder of the from and to tabs.
+        final int fromPosition;
+        final int toPosition;
         synchronized (this) {
-            final int fromPosition;
             if (tabPositionCache.mTabId == fromTabId) {
                 fromPosition = tabPositionCache.mOrderPosition;
             } else {
@@ -1147,7 +1149,7 @@ public class Tabs implements BundleEventListener {
 
             // Start the toPosition search from the mOrder from position.
             final int adjustedToPositionHint = fromPosition + (toPositionHint - fromPositionHint);
-            final int toPosition = getOrderPositionForTab(toTabId, adjustedToPositionHint, fromPositionHint < toPositionHint);
+            toPosition = getOrderPositionForTab(toTabId, adjustedToPositionHint, fromPositionHint < toPositionHint);
             // Remember where the tab was moved to so that if this move continues we'll be ready.
             tabPositionCache.cache(fromTabId, toPosition);
 
@@ -1174,5 +1176,12 @@ public class Tabs implements BundleEventListener {
         }
 
         queuePersistAllTabs();
+
+        final GeckoBundle data = new GeckoBundle();
+        data.putInt("fromTabId", fromTabId);
+        data.putInt("fromPosition", fromPosition);
+        data.putInt("toTabId", toTabId);
+        data.putInt("toPosition", toPosition);
+        EventDispatcher.getInstance().dispatch("Tab:Move", data);
     }
 }

mobile/android/chrome/content/browser.js

@@ -393,6 +393,7 @@ var BrowserApp = {
       "Tab:Load",
       "Tab:Selected",
       "Tab:Closed",
+      "Tab:Move",
       "Browser:LoadManifest",
       "Browser:Quit",
       "Fonts:Reload",
@@ -1316,6 +1317,22 @@ var BrowserApp = {
     this._tabs.splice(tabIndex, 1);
   },
 
+  _handleTabMove(fromTabId, fromPosition, toTabId, toPosition) {
+    let movedTab = this._tabs[fromPosition];
+    if (movedTab.id != fromTabId || this._tabs[toPosition].id != toTabId) {
+      // The gecko and/or java Tabs tabs lists changed sometime between when the Tabs list was
+      // updated and when news of the update arrived here.
+      throw "Moved tab mismatch: (" + fromTabId + ", " + movedTab.id + "), " +
+            "(" + toTabId + ", " + this._tabs[toPosition].id + ")";
+    }
+
+    let step = (fromPosition < toPosition) ? 1 : -1;
+    for (let i = fromPosition; i != toPosition; i += step) {
+      this._tabs[i] = this._tabs[i + step];
+    }
+    this._tabs[toPosition] = movedTab;
+  },
+
   // Use this method to select a tab from JS. This method sends a message
   // to Java to select the tab in the Java UI (we'll get a Tab:Selected message
   // back from Java when that happens).
@@ -1898,6 +1915,10 @@ var BrowserApp = {
         this._handleTabClosed(this.getTabForId(data.tabId), data.showUndoToast);
         break;
       }
+
+      case "Tab:Move":
+        this._handleTabMove(data.fromTabId, data.fromPosition, data.toTabId, data.toPosition);
+        break;
     }
   },