Set background color when adding a new tab.

chrome/browser/ui/browser_unittest.cc

Index: chrome/browser/ui/browser_unittest.cc
diff --git a/chrome/browser/ui/browser_unittest.cc b/chrome/browser/ui/browser_unittest.cc
index 6cfdf0b5f4eab9329772ffc1e20795fc77b523ae..fa7b360d9d006849ada32cc4cced92b9cb3bf1d9 100644
--- a/chrome/browser/ui/browser_unittest.cc
+++ b/chrome/browser/ui/browser_unittest.cc
@@ -11,9 +11,11 @@
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/test/base/browser_with_test_window_test.h"
 #include "components/zoom/zoom_controller.h"
+#include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/test/web_contents_tester.h"
+#include "third_party/skia/include/core/SkColor.h"
 
 using content::SiteInstance;
 using content::WebContents;
@@ -66,6 +68,31 @@ TEST_F(BrowserUnitTest, ReloadCrashedTab) {
   EXPECT_TRUE(contents2->IsCrashed());
 }
 
+TEST_F(BrowserUnitTest, SetBackgroundColorForNewTab) {
+  TabStripModel* tab_strip_model = browser()->tab_strip_model();
+
+  WebContents* contents1 = CreateTestWebContents();
+  tab_strip_model->AppendWebContents(contents1, true);
+  WebContentsTester::For(contents1)->NavigateAndCommit(GURL("about:blank"));
+  WebContentsTester::For(contents1)->TestSetIsLoading(false);
+
+  contents1->GetMainFrame()->GetView()->SetBackgroundColor(SK_ColorRED);
+
+  // Add a second tab in the background.
+  WebContents* contents2 = CreateTestWebContents();
+  tab_strip_model->AppendWebContents(contents2, false);
+  WebContentsTester::For(contents2)->NavigateAndCommit(GURL("about:blank"));
+  WebContentsTester::For(contents2)->TestSetIsLoading(false);
+
+  // Color is only set once the tab is activated.

[Peter Kasting, 2017/03/07 00:28:36]

Why is it important to test this?  It doesn't seem like it would be a bug if we
violated this in the future.

[chrishtr, 2017/03/07 00:36:48]

Fair point. Deleted this part.

+  EXPECT_FALSE(SK_ColorRED ==
+               contents2->GetMainFrame()->GetView()->background_color());
+
+  tab_strip_model->ActivateTabAt(1, true);
+  EXPECT_EQ(SK_ColorRED,
+            contents2->GetMainFrame()->GetView()->background_color());
+}
+
 // Ensure the print command gets disabled when a tab crashes.
 TEST_F(BrowserUnitTest, DisablePrintOnCrashedTab) {
   TabStripModel* tab_strip_model = browser()->tab_strip_model();