Add ink drop ripple (but no highlight) to comboboxes in harmony.

ui/views/controls/prefix_selector_unittest.cc

Index: ui/views/controls/prefix_selector_unittest.cc
diff --git a/ui/views/controls/prefix_selector_unittest.cc b/ui/views/controls/prefix_selector_unittest.cc
index 8619c76229cb92af24464093acce556fb6c88b9f..7f026e82dfddac91e9e094fe5b1993ae07ae53ac 100644
--- a/ui/views/controls/prefix_selector_unittest.cc
+++ b/ui/views/controls/prefix_selector_unittest.cc
@@ -16,7 +16,7 @@ using base::ASCIIToUTF16;
 
 namespace views {
 
-class TestPrefixDelegate : public PrefixDelegate {
+class TestPrefixDelegate : public View, public PrefixDelegate {
  public:
   TestPrefixDelegate() : selected_row_(0) {
     rows_.push_back(ASCIIToUTF16("aardvark"));
@@ -45,7 +45,7 @@ class TestPrefixDelegate : public PrefixDelegate {
 class PrefixSelectorTest : public ViewsTestBase {
  public:
   PrefixSelectorTest() {
-    selector_.reset(new PrefixSelector(&delegate_));
+    selector_.reset(new PrefixSelector(&delegate_, &delegate_));
   }
   ~PrefixSelectorTest() override {
     // Explicitly release |selector_| here which can happen before releasing
@@ -58,7 +58,7 @@ class PrefixSelectorTest : public ViewsTestBase {
   TestPrefixDelegate delegate_;
 
  private:
-    DISALLOW_COPY_AND_ASSIGN(PrefixSelectorTest);
+  DISALLOW_COPY_AND_ASSIGN(PrefixSelectorTest);
 };
 
 TEST_F(PrefixSelectorTest, PrefixSelect) {