Delete code involving overdraw bottom height.

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutRenderHost.java

 // Copyright 2015 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.
 
 package org.chromium.chrome.browser.compositor.layouts;
 
 import android.graphics.Rect;
 
 import org.chromium.chrome.browser.compositor.layouts.components.LayoutTab;
 import org.chromium.ui.resources.ResourceManager;
@@ skipping 22 matching lines @@
      * Indicates that the rendering surface has just been created.
      */
     void onSurfaceCreated();
 
     /**
      * Indicates that the rendering surface has been resized.
      */
     void onPhysicalBackingSizeChanged(int width, int height);
 
     /**
-     * Indicates that the amount the surface is overdrawing on the bottom has changed.
-     *
-     * This occurs when the surface is larger than the window viewport.
-     *
-     * @param overdrawHeight The overdraw amount.
-     */
-    void onOverdrawBottomHeightChanged(int overdrawHeight);
-
-    /**
-     * @see #onOverdrawBottomHeightChanged(int)
-     * @return The overdraw bottom height of the last frame rendered by the current tab.
-     */
-    int getCurrentOverdrawBottomHeight();
-
-    /**
      * @return The number of actually drawn {@link LayoutTab}.
      */
     int getLayoutTabsDrawnCount();
 
     /**
      * Pushes a debug rectangle that will be drawn.
      *
      * @param rect  The rect to be drawn.
      * @param color The color of the rect.
      */
@@ skipping 34 matching lines @@
     /**
      * @return The {@link ResourceManager}.
      */
     ResourceManager getResourceManager();
 
     /**
      * Called when something has changed in the Compositor rendered view system.
      */
     void invalidateAccessibilityProvider();
 }