VrShell: Add test for fullscreen transitions.

chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc

Index: chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc
diff --git a/chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc b/chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc
index b7b840f62fc7a3ec23cca1bd5751d0b6b8e3a7ec..5782c63bc661f663060a4e02d07e7b11a5b2c893 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc
+++ b/chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/android/vr_shell/ui_scene_manager.h"
 
 #include "base/macros.h"
+#include "chrome/browser/android/vr_shell/ui_elements/ui_element.h"
 #include "chrome/browser/android/vr_shell/ui_scene.h"
 #include "chrome/browser/android/vr_shell/vr_browser_interface.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -78,4 +79,44 @@ TEST_F(UiSceneManagerTest, ContentPausesOnAppButtonClick) {
   EXPECT_TRUE(scene_->GetWebVrRenderingEnabled());
 }
 
+TEST_F(UiSceneManagerTest, UiUpdatesForFullscreen) {
+  InSequence s;

[cjgrant, 2017/05/10 02:45:00]

Not needed - it's only required to ensure that mock calls are seen in order.

[amp, 2017/05/10 16:05:55]

Done.

+  // Set mode to not WebVR, everything should be visible.
+  manager_->SetWebVrMode(false);
+
+  // Hold onto the background color to make sure it changes.
+  vr::Colorf initialBackground = scene_->GetBackgroundColor();
+
+  for (UiElement* element : manager_->browser_ui_elements_) {

[cjgrant, 2017/05/10 02:45:00]

browser_ui_elements_ is an internal convenience that I don't think a test should
depend on.  What about inspecting the scene instead? It already exposes the set
of elements, so maybe you can check that all elements that aren't fill NONE or
CONTENT are hidden?

Alternatively, we had previously attached descriptive strings to elements, but
removed them to keep them out of the binary.  What if we made an enum of
elements instead, assigning values to elements that tests care about?  Then
tests can identify elements in cases like this.  Thoughts?

[amp, 2017/05/10 16:05:55]

Thanks for the suggestion.  I had tried this at first, but the only method I saw
then was the GetWorldElements method which does a check on calculated opacity
and didn't return anything so I gave up and went the internal route.  After
reading your comment I went back and checked and realized that there was
GetUiElements that returns all of them.  Your suggestion of checking the fill
type sounds like it should work.
We might end up going that route eventually, but I think I can make it work with
just checking the fill types for now (as the CONTENT type is the main one I care
about).  Once we start checking for other things we may need to have add some
mapping via enum's etc.

+    EXPECT_TRUE(element->visible());
+  }
+
+  manager_->SetFullscreen(true);
+
+  // All elements should be hidden except for main content.
+  for (UiElement* element : manager_->browser_ui_elements_) {
+    if (element == manager_->main_content_) {
+      EXPECT_TRUE(element->visible());
+      continue;
+    }
+    EXPECT_FALSE(element->visible());
+  }
+  // Make sure background has changed for fullscreen.
+  EXPECT_NE(initialBackground.r, scene_->GetBackgroundColor().r);
+  EXPECT_NE(initialBackground.g, scene_->GetBackgroundColor().g);
+  EXPECT_NE(initialBackground.b, scene_->GetBackgroundColor().b);
+  // Alpha doesn't change
+
+  manager_->SetFullscreen(false);
+
+  // Everything should return to original state after leaving fullscreen.
+  for (UiElement* element : manager_->browser_ui_elements_) {
+    EXPECT_TRUE(element->visible());
+  }
+  EXPECT_EQ(initialBackground.r, scene_->GetBackgroundColor().r);
+  EXPECT_EQ(initialBackground.g, scene_->GetBackgroundColor().g);
+  EXPECT_EQ(initialBackground.b, scene_->GetBackgroundColor().b);
+  EXPECT_EQ(initialBackground.a, scene_->GetBackgroundColor().a);
+}
+
 }  // namespace vr_shell