Add more components_unittests to GN build

components/dom_distiller/content/BUILD.gn

Index: components/dom_distiller/content/BUILD.gn
diff --git a/components/dom_distiller/content/BUILD.gn b/components/dom_distiller/content/BUILD.gn
index 9ba3899d8fc524ed08fff4e6f1bb322a23a82e52..7f018a9f41ef24d045ff441642d1e9cbd4963504 100644
--- a/components/dom_distiller/content/BUILD.gn
+++ b/components/dom_distiller/content/BUILD.gn
@@ -2,55 +2,67 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-if (!is_ios) {
-  # GYP version: components/dom_distiller.gypi:dom_distiller_content
-  static_library("content_browser") {
-    sources = [
-      "browser/distillable_page_utils.cc",
-      "browser/distillable_page_utils.h",
-      "browser/distiller_javascript_utils.cc",
-      "browser/distiller_javascript_utils.h",
-      "browser/distiller_page_web_contents.cc",
-      "browser/distiller_page_web_contents.h",
-      "browser/dom_distiller_viewer_source.cc",
-      "browser/dom_distiller_viewer_source.h",
-      "browser/external_feedback_reporter.h",
-      "browser/web_contents_main_frame_observer.cc",
-      "browser/web_contents_main_frame_observer.h",
-    ]
+assert(!is_ios)
 
-    public_deps = [
-      "//components/dom_distiller/core",
-    ]
-    deps = [
-      "//base",
-      "//components/resources",
-      "//components/strings",
-      "//content/public/browser",
-      "//net",
-      "//skia",
-      "//sync",
-      "//ui/gfx",
-      "//url",
-    ]
+# GYP version: components/dom_distiller.gypi:dom_distiller_content
+source_set("content_browser") {
+  sources = [
+    "browser/distillable_page_utils.cc",
+    "browser/distillable_page_utils.h",
+    "browser/distiller_javascript_utils.cc",
+    "browser/distiller_javascript_utils.h",
+    "browser/distiller_page_web_contents.cc",
+    "browser/distiller_page_web_contents.h",
+    "browser/dom_distiller_viewer_source.cc",
+    "browser/dom_distiller_viewer_source.h",
+    "browser/external_feedback_reporter.h",
+    "browser/web_contents_main_frame_observer.cc",
+    "browser/web_contents_main_frame_observer.h",
+  ]
 
-    if (is_android) {
-      sources += [
-        "browser/distillable_page_utils_android.cc",
-        "browser/distillable_page_utils_android.h",
-      ]
-      deps += [ ":jni_headers" ]
-    }
-  }
+  public_deps = [
+    "//components/dom_distiller/core",
+    "//content/public/browser",
+  ]
+  deps = [
+    "//base",
+    "//components/resources",
+    "//components/strings",
+    "//net",
+    "//skia",
+    "//sync",
+    "//ui/gfx",
+    "//url",
+  ]
 
   if (is_android) {
-    import("//build/config/android/rules.gni")
+    sources += [
+      "browser/distillable_page_utils_android.cc",
+      "browser/distillable_page_utils_android.h",
+    ]
+    deps += [ ":jni_headers" ]
+  }
+}
+
+if (is_android) {
+  import("//build/config/android/rules.gni")
 
-    generate_jni("jni_headers") {
-      sources = [
-        "../android/java/src/org/chromium/components/dom_distiller/content/DistillablePageUtils.java",
-      ]
-      jni_package = "dom_distiller_content"
-    }
+  generate_jni("jni_headers") {
+    sources = [
+      "../android/java/src/org/chromium/components/dom_distiller/content/DistillablePageUtils.java",
+    ]
+    jni_package = "dom_distiller_content"
   }
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "browser/dom_distiller_viewer_source_unittest.cc",
+    "browser/web_contents_main_frame_observer_unittest.cc",
+  ]
+  deps = [
+    ":content_browser",
+    "//testing/gtest",
+  ]
+}