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 f803c835f69dbfef66b239321cbe090b9b8c975b..6fe133bc498eaf3cf17a56a91ab1fbaf09503b55 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"
@@ -72,4 +73,52 @@ TEST_F(UiSceneManagerTest, ExitPresentOnAppButtonClick) {
   manager_->OnAppButtonClicked();
 }
 
+TEST_F(UiSceneManagerTest, UiUpdatesForFullscreen) {
+  InSequence s;

[cjgrant, 2017/05/10 18:50:22]

I think you said removing this was Done. :)

[amp, 2017/05/10 21:43:43]

Oops, must of slipped through the cracks as I was switching branches.  I thought
I had removed it...

+  // Set mode to not fullscreen, everything should be visible.
+  manager_->SetFullscreen(false);
+
+  // Hold onto the background color to make sure it changes.
+  vr::Colorf initialBackground = scene_->GetBackgroundColor();
+
+  for (const auto& element : scene_->GetUiElements()) {

[cjgrant, 2017/05/10 18:50:22]

Thinking about this more.  This should be tripping on the invisible HTTP
warnings, but it doesn't, because in tests, nobody initializes the GL-based
textures for elements, and hence the elements aren't updated to Fill::SELF.  So
with this method, it seems the test would be falsely working.

Sorry to have kibosh'ed the original approach.  I still don't think it was
better, but maybe it can be adapted to have scene manager offer a
GetElementsVisibleInBrowserMode(), usable here.  You wouldn't need the friend
accessibility, but just as before, we're taking advantage of an implementation
detail of scene manager to test scene manager.  I think the enum approach might
be best, so we can have a test that's like:

for element : elements {
  should_be_visible = set({URL_BAR, PROGRESS_INDICATOR,. ...).has(element.name);
  EXPECT_EQ(should_be_visible, element.IsVisible()
}

Feel free to message offline about this...  I could be crazy.

[amp, 2017/05/10 21:43:43]

Per offline discussion I'll go with something like the proposed enums.  Stay
tuned!

+    if (element->fill() != vr_shell::Fill::NONE) {
+      EXPECT_TRUE(element->visible());
+    }
+  }
+
+  // Transistion to fullscreen.
+  manager_->SetFullscreen(true);
+
+  // All elements should be hidden except for main content.
+  for (const auto& element : scene_->GetUiElements()) {
+    if (element->fill() == vr_shell::Fill::CONTENT) {
+      EXPECT_TRUE(element->visible());
+      continue;
+    }
+    if (element->fill() != vr_shell::Fill::NONE) {
+      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
+
+  // Exit fullscreen.
+  manager_->SetFullscreen(false);
+
+  // Everything should return to original state after leaving fullscreen.
+  for (const auto& element : scene_->GetUiElements()) {
+    if (element->fill() != vr_shell::Fill::NONE) {
+      EXPECT_TRUE(element->visible());
+    }
+  }
+  EXPECT_EQ(initialBackground.r, scene_->GetBackgroundColor().r);

[cjgrant, 2017/05/17 14:40:11]

Revisiting the helper method approach here, see gtest's SCOPED_TRACE() - it
looks helpful.

+  EXPECT_EQ(initialBackground.g, scene_->GetBackgroundColor().g);
+  EXPECT_EQ(initialBackground.b, scene_->GetBackgroundColor().b);
+  EXPECT_EQ(initialBackground.a, scene_->GetBackgroundColor().a);
+}
+
 }  // namespace vr_shell