Update touch selection to only modify one selection point at a time.

content/browser/android/content_view_core_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/android/content_view_core_impl.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 759 matching lines @@
   root_layer_->SetIsDrawable(false);
 }
 
 void ContentViewCoreImpl::RemoveLayer(scoped_refptr<cc::Layer> layer) {
   layer->RemoveFromParent();
 
   if (!root_layer_->children().size())
     root_layer_->SetIsDrawable(true);
 }
 
+void ContentViewCoreImpl::MoveSelectionExtent(const gfx::PointF& position) {
+  if (!web_contents_)
+    return;
+
+  web_contents_->MoveSelectionExtent(gfx::Point(position.x(), position.y()));
+}
+
 void ContentViewCoreImpl::SelectBetweenCoordinates(const gfx::PointF& start,
                                                    const gfx::PointF& end) {
   if (!web_contents_)
     return;
 
   gfx::Point start_point = gfx::Point(start.x(), start.y());
   gfx::Point end_point = gfx::Point(end.x(), end.y());
   if (start_point == end_point)
     return;
 
@@ skipping 548 matching lines @@
       reinterpret_cast<ui::WindowAndroid*>(window_android),
       retained_objects_set);
   return reinterpret_cast<intptr_t>(view);
 }
 
 bool RegisterContentViewCore(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content