Add test for check_webapp_display_manifest being false.

This option was added recently without any tests. This change adds a
simple test for this.

Bug: 902937
Change-Id: If35b91e8c43db434921a0a6b01beb708957aecb3
Reviewed-on: https://chromium-review.googlesource.com/c/1343813
Commit-Queue: Ben Wells <benwells@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609925}

chrome/browser/installable/installable_manager_unittest.cc

@@ -38,11 +38,12 @@ class InstallableManagerUnitTest : public testing::Test {
     return manifest;
   }
 
-  bool IsManifestValid(const blink::Manifest& manifest) {
+  bool IsManifestValid(const blink::Manifest& manifest,
+                       bool check_webapp_manifest_display = true) {
     // Explicitly reset the error code before running the method.
     manager_->set_valid_manifest_error(NO_ERROR_DETECTED);
-    return manager_->IsManifestValidForWebApp(
-        manifest, true /* check_webapp_manifest_display */);
+    return manager_->IsManifestValidForWebApp(manifest,
+                                              check_webapp_manifest_display);
   }
 
   InstallableStatusCode GetErrorCode() {
@@ -189,10 +190,14 @@ TEST_F(InstallableManagerUnitTest, ManifestDisplayModes) {
   blink::Manifest manifest = GetValidManifest();
 
   manifest.display = blink::kWebDisplayModeUndefined;
+  EXPECT_TRUE(
+      IsManifestValid(manifest, false /* check_webapp_manifest_display */));
   EXPECT_FALSE(IsManifestValid(manifest));
   EXPECT_EQ(MANIFEST_DISPLAY_NOT_SUPPORTED, GetErrorCode());
 
   manifest.display = blink::kWebDisplayModeBrowser;
+  EXPECT_TRUE(
+      IsManifestValid(manifest, false /* check_webapp_manifest_display */));
   EXPECT_FALSE(IsManifestValid(manifest));
   EXPECT_EQ(MANIFEST_DISPLAY_NOT_SUPPORTED, GetErrorCode());