Fix unit tests that use OmniboxViewViews in Refresh.

Some tests would create an instance of OmniboxViewViews, but without a
location bar. Refresh tries to access the location bar to set the
placeholder text, and this would crash. This patch moves that code into
Init and guards it by checking that location_bar_view_ is defined.

Bug: 846410
Change-Id: I0a1aec21f515dcc441e52c92c0c1adc58163348f
Reviewed-on: https://chromium-review.googlesource.com/1098141Reviewed-by: Tommy Li <tommycli@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566682}

chrome/browser/ui/views/omnibox/omnibox_view_views.cc

@@ -139,12 +139,6 @@ OmniboxViewViews::OmniboxViewViews(OmniboxEditController* controller,
       scoped_template_url_service_observer_(this) {
   set_id(VIEW_ID_OMNIBOX);
   SetFontList(font_list);
-
-  if (ui::MaterialDesignController::IsNewerMaterialUi()) {
-    InstallPlaceholderText();
-    scoped_template_url_service_observer_.Add(
-        model()->client()->GetTemplateURLService());
-  }
 }
 
 OmniboxViewViews::~OmniboxViewViews() {
@@ -167,6 +161,11 @@ void OmniboxViewViews::Init() {
     SetReadOnly(true);
 
   if (location_bar_view_) {
+    if (ui::MaterialDesignController::IsNewerMaterialUi()) {
+      InstallPlaceholderText();
+      scoped_template_url_service_observer_.Add(
+          model()->client()->GetTemplateURLService());
+    }
     // Initialize the popup view using the same font.
     popup_view_.reset(
         new OmniboxPopupContentsView(this, model(), location_bar_view_));