Support dragging texts out of webview/Chrome.

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index 52504aa283d14a75704e5c9c9d2069176c81f6b1..5310a0ba553517ee3fe164b3435e9166c27c0b96 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -47,6 +47,7 @@ import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;
 import android.view.inputmethod.InputMethodManager;
 import android.widget.FrameLayout;
+import android.widget.ImageView;
 
 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.CommandLine;
@@ -115,6 +116,9 @@ public class ContentViewCore implements AccessibilityStateChangeListener, Screen
     // produce little visible difference.
     private static final float ZOOM_CONTROLS_EPSILON = 0.007f;
 
+    // TODO(hush): use View#DRAG_FLAG_GLOBAL when Chromium starts to build with API 24.
+    private static final int DRAG_FLAG_GLOBAL = 1 << 8;
+
     private static final ZoomControlsDelegate NO_OP_ZOOM_CONTROLS_DELEGATE =
             new ZoomControlsDelegate() {
         @Override
@@ -3330,6 +3334,20 @@ public class ContentViewCore implements AccessibilityStateChangeListener, Screen
         return true;
     }
 
+    @CalledByNative
+    private void startDragging(String draggedText, Bitmap dragShadowImage) {
+        ClipData data = ClipData.newPlainText(null, draggedText);
+
+        ImageView imageView = new ImageView(mContext);
+        imageView.setImageBitmap(dragShadowImage);
+        imageView.layout(0, 0, dragShadowImage.getWidth(), dragShadowImage.getHeight());
+
+        // TODO(hush): use View#startDragAndDrop when Chromium starts to build with API 24.
+        mContainerView.startDrag(
+                data, new View.DragShadowBuilder(imageView), null, DRAG_FLAG_GLOBAL);
+        hidePopupsAndPreserveSelection();
+    }
+
     /**
      * Offer a long press gesture to the embedding View, primarily for WebView compatibility.
      *