Initiate Hotseat drag from long pressing corresponding Taskbar item

When you long press on the taskbar hotseat item, the following happens:
- We start a system drag and drop with an invisible drag shadow
- We create a new DragOptions with the simulatedDndStartPoint set to the
  drag down position, and tell Launcher to use that for the next drag
- We perform a long click on the equivalent Hotseat item in Launcher
- We pass the drag events of that operation to Launcher's DragController

This allows Launcher to handle the entire drag operation, including the
pre-drag (with popup), and taskbar already hides when the drag starts.

Test: Long press items in taskbar hotseat, able to drag them to workspace

Bug: 179886115
Bug: 171917176
Change-Id: I576b80cb1bd0225cdc91cf7689fdee0481265109
diff --git a/src/com/android/launcher3/Hotseat.java b/src/com/android/launcher3/Hotseat.java
index ebaacb6..b2112ad 100644
--- a/src/com/android/launcher3/Hotseat.java
+++ b/src/com/android/launcher3/Hotseat.java
@@ -21,6 +21,7 @@
 import android.util.AttributeSet;
 import android.view.Gravity;
 import android.view.MotionEvent;
+import android.view.View;
 import android.view.ViewDebug;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
@@ -166,4 +167,11 @@
     protected void showInlineQsb() {
         //Does nothing
     }
+
+    /**
+     * Returns the first View for which the given itemOperator returns true, or null.
+     */
+    public View getFirstItemMatch(Workspace.ItemOperator itemOperator) {
+        return mWorkspace.getFirstMatch(new CellLayout[] { this }, itemOperator);
+    }
 }
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 253a7c7..fa63885 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -121,6 +121,7 @@
 import com.android.launcher3.dot.DotInfo;
 import com.android.launcher3.dragndrop.DragController;
 import com.android.launcher3.dragndrop.DragLayer;
+import com.android.launcher3.dragndrop.DragOptions;
 import com.android.launcher3.dragndrop.DragView;
 import com.android.launcher3.folder.FolderGridOrganizer;
 import com.android.launcher3.folder.FolderIcon;
@@ -2863,6 +2864,10 @@
         return false;
     }
 
+    public DragOptions getDefaultWorkspaceDragOptions() {
+        return new DragOptions();
+    }
+
     private static class NonConfigInstance {
         public Configuration config;
         public Bitmap snapshot;
diff --git a/src/com/android/launcher3/Workspace.java b/src/com/android/launcher3/Workspace.java
index 77fee08..87fb6fb 100644
--- a/src/com/android/launcher3/Workspace.java
+++ b/src/com/android/launcher3/Workspace.java
@@ -2973,7 +2973,7 @@
      * @param operators List of operators, in order starting from best matching operator.
      * @return
      */
-    private View getFirstMatch(CellLayout[] cellLayouts, final ItemOperator... operators) {
+    View getFirstMatch(CellLayout[] cellLayouts, final ItemOperator... operators) {
         // This array is filled with the first match for each operator.
         final View[] matches = new View[operators.length];
         // For efficiency, the outer loop should be CellLayout.
diff --git a/src/com/android/launcher3/touch/ItemLongClickListener.java b/src/com/android/launcher3/touch/ItemLongClickListener.java
index 919673f..f876dd9 100644
--- a/src/com/android/launcher3/touch/ItemLongClickListener.java
+++ b/src/com/android/launcher3/touch/ItemLongClickListener.java
@@ -57,7 +57,7 @@
         if (!(v.getTag() instanceof ItemInfo)) return false;
 
         launcher.setWaitingForResult(null);
-        beginDrag(v, launcher, (ItemInfo) v.getTag(), new DragOptions());
+        beginDrag(v, launcher, (ItemInfo) v.getTag(), launcher.getDefaultWorkspaceDragOptions());
         return true;
     }