aw scroll instrumentation test has precision issue

AndroidScrollIntegrationTest.testUiScrollReflectedInJs has a precision issue
when enabling --use-zoom-for-dsf. It is the same problem with the one described
in crrev.com/c/844266. In crrev.com/c/844266, I did not apply the same thing to
AndroidScrollIntegrationTest.testUiScrollReflectedInJs as a mistake.

Bug: 737777
Change-Id: I9474e8cf424ed2bf6b10578ab3c7ff7fbf8b6c4b
Reviewed-on: https://chromium-review.googlesource.com/892782Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Jaebaek Seo <jaebaek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533127}

android_webview/javatests/src/org/chromium/android_webview/test/AndroidScrollIntegrationTest.java

@@ -324,6 +324,13 @@ public class AndroidScrollIntegrationTest {
         final int targetScrollYPix = (int) Math.ceil(targetScrollYCss * deviceDIPScale);
         final JavascriptEventObserver onscrollObserver = new JavascriptEventObserver();
 
+        double expectedScrollXCss = targetScrollXCss;
+        double expectedScrollYCss = targetScrollYCss;
+        if (UseZoomForDSFPolicy.isUseZoomForDSFEnabled()) {
+            expectedScrollXCss = (double) targetScrollXPix / deviceDIPScale;
+            expectedScrollYCss = (double) targetScrollYPix / deviceDIPScale;
+        }
+
         InstrumentationRegistry.getInstrumentation().runOnMainSync(() ->
                 onscrollObserver.register(testContainerView.getWebContents(), "onscrollObserver"));
 
@@ -332,8 +339,8 @@ public class AndroidScrollIntegrationTest {
         scrollToOnMainSync(testContainerView, targetScrollXPix, targetScrollYPix);
 
         onscrollObserver.waitForEvent(WAIT_TIMEOUT_MS);
-        assertScrollInJs(testContainerView.getAwContents(), contentsClient,
-                targetScrollXCss, targetScrollYCss);
+        assertScrollInJs(testContainerView.getAwContents(), contentsClient, expectedScrollXCss,
+                expectedScrollYCss);
     }
 
     @Test