Fix a crash where the dragged content does not contain any text.

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 a79db6829d88b8c45b7e16e00ea747d7b5ce68b7..6f92c8764312c8736e88d2a3cfc13c27f43cdf9d 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
@@ -3160,7 +3160,8 @@ public class ContentViewCore implements AccessibilityStateChangeListener, Screen
 
         if (event.getAction() == DragEvent.ACTION_DRAG_STARTED) {
             // TODO(hush): support dragging more than just text.
-            return mimeTypes.length > 0 && nativeIsTouchDragDropEnabled(mNativeContentViewCore);
+            return mimeTypes != null && mimeTypes.length > 0 &&
+                    nativeIsTouchDragDropEnabled(mNativeContentViewCore);
         }
 
         StringBuilder content = new StringBuilder("");