📷 Enable Render Tests.

Make the render tests fail if the rendered bitmap does not match the
golden.

Bug: 641973
Change-Id: I432111296893bafab18dc65bfb62b12a8212d68e
Reviewed-on: https://chromium-review.googlesource.com/565399
Commit-Queue: Peter Conn <peconn@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488631}

chrome/test/android/javatests/src/org/chromium/chrome/test/util/RenderTestRule.java

@@ -74,11 +74,11 @@ public class RenderTestRule extends TestWatcher {
     private static final String[] RENDER_TEST_DEVICES = {"Nexus 5X", "Nexus 5"};
 
     /**
-     * Before we know how flaky screenshot tests are going to be we don't want them to cause a
-     * full test failure every time they fail. If the tests prove their worth, this will be set to
-     * false/removed.
+     * We only want to cause the tests to fail when renders mismatch for devices that we test on
+     * both the CI and the CQ. This is temporary and will be removed once all the
+     * {@link RENDER_TEST_DEVICES} are run on the CI and CQ. https://crbug.com/731759.
      */
-    private static final boolean REPORT_ONLY_DO_NOT_FAIL = true;
+    private static final String[] FAIL_ON_MISMATCH_DEVICES = {"Nexus 5"};
 
     /** How many pixels can be different in an image before counting the images as different. */
     private static final int PIXEL_DIFF_THRESHOLD = 0;
@@ -198,10 +198,10 @@ public class RenderTestRule extends TestWatcher {
             sb.append(TextUtils.join(", ", mMismatchIds));
         }
 
-        if (REPORT_ONLY_DO_NOT_FAIL) {
-            Log.w(TAG, sb.toString());
-        } else {
+        if (shouldFailOnMismatch()) {
             throw new RenderTestException(sb.toString());
+        } else {
+            Log.w(TAG, sb.toString());
         }
     }
 
@@ -215,6 +215,16 @@ public class RenderTestRule extends TestWatcher {
         return false;
     }
 
+    /**
+     * Returns whether a mismatch should cause a test failure.
+     */
+    private static boolean shouldFailOnMismatch() {
+        for (String model : FAIL_ON_MISMATCH_DEVICES) {
+            if (model.equals(Build.MODEL)) return true;
+        }
+        return false;
+    }
+
     /**
      * Creates an image name combining the image description with details about the device
      * (eg model, current orientation).