[Android] Implement scrollTo in terms of scrollBy

content/public/android/javatests/src/org/chromium/content/browser/ContentViewScrollingTest.java

 // 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.
 
 package org.chromium.content.browser;
 
 import android.content.res.Configuration;
 import android.graphics.Canvas;
 import android.os.SystemClock;
 import android.test.suitebuilder.annotation.SmallTest;
@@ skipping 118 matching lines @@
 
     private void scrollTo(final int x, final int y) throws Throwable {
         runTestOnUiThread(new Runnable() {
             @Override
             public void run() {
                 getContentViewCore().getContainerView().scrollTo(x, y);
             }
         });
     }
 
+    private void scrollBy(final int dx, final int dy) throws Throwable {
+        runTestOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                getContentViewCore().getContainerView().scrollBy(dx, dy);
+            }
+        });
+    }
+
     @Override
     protected void setUp() throws Exception {
         super.setUp();
 
         launchContentShellWithUrl(LARGE_PAGE);
         assertTrue("Page failed to load", waitForActiveShellToBeDoneLoading());
         assertWaitForPageScaleFactorMatch(2.0f);
 
         assertEquals(0, getContentViewCore().getNativeScrollXForTest());
         assertEquals(0, getContentViewCore().getNativeScrollYForTest());
@@ skipping 25 matching lines @@
         assertWaitForScroll(true, true);
 
         // Diagonal fling to bottom-right.
         fling(-velocity, -velocity);
         assertWaitForScroll(false, false);
     }
 
     @SmallTest
     @RerunWithUpdatedContainerView
     @Feature({"Main"})
-    public void testScroll() throws Throwable {
+    public void testScrollTo() throws Throwable {
         // Vertical scroll to lower-left.
         scrollTo(0, 2500);
         assertWaitForScroll(true, false);
 
         // Horizontal scroll to lower-right.
         scrollTo(2500, 2500);
         assertWaitForScroll(false, false);
 
         // Vertical scroll to upper-right.
         scrollTo(2500, 0);
         assertWaitForScroll(false, true);
 
         // Horizontal scroll to top-left.
         scrollTo(0, 0);
         assertWaitForScroll(true, true);
 
         // Diagonal scroll to bottom-right.
         scrollTo(2500, 2500);
         assertWaitForScroll(false, false);
     }
 
+    @SmallTest
+    @RerunWithUpdatedContainerView
+    @Feature({"Main"})
+    public void testScrollBy() throws Throwable {
+        scrollTo(0, 0);
+        assertWaitForScroll(true, true);
+
+        // No scroll
+        scrollBy(0, 0);
+        assertWaitForScroll(true, true);
+
+        // Vertical scroll to lower-left.
+        scrollBy(0, 2500);
+        assertWaitForScroll(true, false);
+
+        // Horizontal scroll to lower-right.
+        scrollBy(2500, 0);
+        assertWaitForScroll(false, false);
+
+        // Vertical scroll to upper-right.
+        scrollBy(0, -2500);
+        assertWaitForScroll(false, true);
+
+        // Horizontal scroll to top-left.
+        scrollBy(-2500, 0);
+        assertWaitForScroll(true, true);
+
+        // Diagonal scroll to bottom-right.
+        scrollBy(2500, 2500);
+        assertWaitForScroll(false, false);
+    }
+
     /**
      * To ensure the device properly responds to bounds-exceeding scrolls, e.g., overscroll
      * effects are properly initialized.
      */
     @SmallTest
     @RerunWithUpdatedContainerView
     @Feature({"Main"})
     public void testOverScroll() throws Throwable {
         // Overscroll lower-left.
         scrollTo(-10000, 10000);
@@ skipping 36 matching lines @@
         scrollTo(scrollToX, scrollToY);
         assertWaitForScroll(false, false);
         assertTrue(CriteriaHelper.pollForCriteria(new Criteria() {
             @Override
             public boolean isSatisfied() {
                 return containerViewInternals.isScrollChanged();
             }
         }));
     }
 }