Revert "Render snippets in ArticleSnippetsTest in isolation"

This reverts commit ab640662.

Reason for revert: ArticleSnippetsTest has failed consistently
on KitKat Tablet Tester since this landed. Specifically the
following tests are failing:
  ArticleSnippetsTest#testDownloadSuggestion__ChromeHomeEnabled
  ArticleSnippetsTest#testSigninPromo__ChromeHomeEnabled
  ArticleSnippetsTest#testSnippetAppearance__ChromeHomeEnabled

Additionally, many other test suites that follow
chrome_public_test_apk started failing when this landed; not
sure if that's related.

Original change's description:
> Render snippets in ArticleSnippetsTest in isolation
> 
> Remove the "snippets" render that shows all cards together, because
> multiple, non-article sections are not realistic in the modern design
> anymore.
> 
> Rebaseline other renders:
> * Use relative timestamp instead of Jan 17, 1970
> * Use only single-card backgrounds for pre-modern cards
> * Update modern card background color after https://crrev.com/497799
> * Update pre-modern text color after https://crrev.com/500684
> 
> Also move card contents in the modern layout except for the rounded
> corners into a RelativeLayout, to avoid a circular dependency between
> the height of the containing layout and the position of the bottom
> corner (see https://developer.android.com/reference/android/widget/RelativeLayout.html).
> 
> Bug: 757735
> Change-Id: I81add3d5bdd8ffec61b9e8aa2ff3a9caa44ccf91
> Reviewed-on: https://chromium-review.googlesource.com/628562
> Commit-Queue: Bernhard Bauer <bauerb@chromium.org>
> Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
> Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
> Reviewed-by: Peter Conn <peconn@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#500975}

TBR=bauerb@chromium.org,skyostil@chromium.org,perezju@chromium.org,peconn@chromium.org

Change-Id: Iedb4e042448a8e4c8090d8af5fbdbb6e2f19a6b7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 757735
Reviewed-on: https://chromium-review.googlesource.com/663382Reviewed-by: John Mellor <johnme@chromium.org>
Commit-Queue: John Mellor <johnme@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501269}

build/android/findbugs_filter/findbugs_exclude.xml

@@ -32,7 +32,7 @@ In particular, ~ at the start of a string means it's a regex.
   -->
   <Bug pattern="BC_UNCONFIRMED_CAST" />
 
-  <!-- Ignore unused public rules and implementations thereof in instrumentation tests -->
+  <!-- Ignore unused public Rule and RuleChain in instrumentation tests -->
   <Match>
     <Class name="~.*\.*Test" />
     <Field type="android.support.test.rule.UiThreadTestRule" />
@@ -43,10 +43,5 @@ In particular, ~ at the start of a string means it's a regex.
     <Field type="org.junit.rules.RuleChain" />
     <Bug pattern="URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD" />
   </Match>
-  <Match>
-    <Class name="~.*\.*Test" />
-    <Field type="org.junit.rules.TestRule" />
-    <Bug pattern="URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD" />
-  </Match>
 
 </FindBugsFilter>

chrome/test/android/BUILD.gn

@@ -31,7 +31,6 @@ android_library("chrome_java_test_support") {
     "javatests/src/org/chromium/chrome/test/util/ApplicationData.java",
     "javatests/src/org/chromium/chrome/test/util/ApplicationTestUtils.java",
     "javatests/src/org/chromium/chrome/test/util/BookmarkTestUtil.java",
-    "javatests/src/org/chromium/chrome/test/util/browser/compositor/layouts/DisableChromeAnimations.java",
     "javatests/src/org/chromium/chrome/test/util/browser/contextmenu/ContextMenuUtils.java",
     "javatests/src/org/chromium/chrome/test/util/browser/Features.java",
     "javatests/src/org/chromium/chrome/test/util/browser/LocationSettingsTestUtil.java",

chrome/test/android/javatests/src/org/chromium/chrome/test/util/browser/compositor/layouts/DisableChromeAnimations.java

-// Copyright 2017 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.test.util.browser.compositor.layouts;
-
-import org.junit.rules.ExternalResource;
-
-import org.chromium.chrome.browser.compositor.layouts.ChromeAnimation;
-
-/**
- * JUnit 4 rule that disables animations in ChromeAnimation for tests.
- */
-public class DisableChromeAnimations extends ExternalResource {
-    private float mOldAnimationMultiplier;
-
-    @Override
-    protected void before() {
-        mOldAnimationMultiplier = ChromeAnimation.Animation.getAnimationMultiplier();
-        ChromeAnimation.Animation.setAnimationMultiplierForTesting(0f);
-    }
-
-    @Override
-    protected void after() {
-        ChromeAnimation.Animation.setAnimationMultiplierForTesting(mOldAnimationMultiplier);
-    }
-}