customtabs: Pre-create a renderer in mayLaunchUrl().

chrome/browser/history/android/android_provider_backend_unittest.cc

Index: chrome/browser/history/android/android_provider_backend_unittest.cc
diff --git a/chrome/browser/history/android/android_provider_backend_unittest.cc b/chrome/browser/history/android/android_provider_backend_unittest.cc
index 72d09bfe0f8bbe947ccd436725af5eec6f2d6470..cbd4daf03f81529e020698249cc62b7d21ecc1fe 100644
--- a/chrome/browser/history/android/android_provider_backend_unittest.cc
+++ b/chrome/browser/history/android/android_provider_backend_unittest.cc
@@ -263,6 +263,11 @@ class AndroidProviderBackendTest : public testing::Test {
   DISALLOW_COPY_AND_ASSIGN(AndroidProviderBackendTest);
 };
 
+TEST_F(AndroidProviderBackendTest, IgnoreAboutBlank) {
+  GURL url("about:blank");
+  ASSERT_FALSE(history_client_->CanAddURL(url));
+}
+
 TEST_F(AndroidProviderBackendTest, UpdateTables) {
   GURL url1("http://www.cnn.com");
   URLID url_id1 = 0;