[vr] Restore opacity when transient elements are shown again.

We'd previously set opacity to 0.0 when hiding elements in the
transience manager which makes it tricky to see them when they come
back. With this change, we inform the manager of the desired "opacity
when visible" and it will restore elements to that opacity when
shown again.

Bug: None
Change-Id: I1a941c3032c35adab5afed17a8afc60bd41230f5
Reviewed-on: https://chromium-review.googlesource.com/582069
Commit-Queue: Ian Vollick <vollick@chromium.org>
Reviewed-by: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488788}

chrome/browser/vr/elements/simple_textured_element.h

@@ -44,7 +44,8 @@ class TransientSimpleTexturedElement : public SimpleTexturedElement<T> {
  public:
   TransientSimpleTexturedElement(int maximum_width,
                                  const base::TimeDelta& timeout)
-      : SimpleTexturedElement<T>(maximum_width), transience_(this, timeout) {}
+      : SimpleTexturedElement<T>(maximum_width),
+        transience_(this, 1.0f, timeout) {}
 
   ~TransientSimpleTexturedElement() override {}
 

chrome/browser/vr/elements/transience_manager.cc

@@ -7,8 +7,11 @@
 namespace vr {
 
 TransienceManager::TransienceManager(UiElement* element,
+                                     float opacity_when_enabled,
                                      const base::TimeDelta& timeout)
-    : element_(element), timeout_(timeout) {
+    : element_(element),
+      opacity_when_enabled_(opacity_when_enabled),
+      timeout_(timeout) {
   element_->SetVisible(false);
 }
 
@@ -17,24 +20,24 @@ void TransienceManager::SetEnabled(bool enabled) {
     return;
   enabled_ = enabled;
   if (enabled) {
-    element_->SetVisible(true);
+    Show();
     StartTimer();
   } else {
-    element_->SetVisible(false);
+    Hide();
     visibility_timer_.Stop();
   }
 }
 
 void TransienceManager::KickVisibilityIfEnabled() {
   if (enabled_) {
-    element_->SetVisible(true);
+    Show();
     StartTimer();
   }
 }
 
 void TransienceManager::EndVisibilityIfEnabled() {
   if (enabled_) {
-    element_->SetVisible(false);
+    Hide();
     visibility_timer_.Stop();
   }
 }
@@ -46,6 +49,15 @@ void TransienceManager::StartTimer() {
 }
 
 void TransienceManager::OnTimeout() {
+  Hide();
+}
+
+void TransienceManager::Show() {
+  element_->SetVisible(true);
+  element_->SetOpacity(opacity_when_enabled_);
+}
+
+void TransienceManager::Hide() {
   element_->SetVisible(false);
   element_->SetOpacity(0);
 }

chrome/browser/vr/elements/transience_manager.h

@@ -15,7 +15,9 @@ namespace vr {
 
 class TransienceManager {
  public:
-  TransienceManager(UiElement* element, const base::TimeDelta& timeout);
+  TransienceManager(UiElement* element,
+                    float opacity_when_enabled,
+                    const base::TimeDelta& timeout);
   virtual ~TransienceManager() = default;
 
   void SetEnabled(bool enabled);
@@ -25,8 +27,11 @@ class TransienceManager {
  private:
   void StartTimer();
   void OnTimeout();
+  void Show();
+  void Hide();
 
   UiElement* element_;
+  float opacity_when_enabled_;
   base::TimeDelta timeout_;
   bool enabled_ = false;
   base::OneShotTimer visibility_timer_;

chrome/browser/vr/elements/transience_manager_unittest.cc

@@ -18,42 +18,57 @@ TEST(TransienceManager, Visibility) {
   base::ScopedMockTimeMessageLoopTaskRunner task_runner_;
 
   UiElement element;
+  float opacity_when_enabled = 0.8;
+  element.SetOpacity(0.0f);
 
-  TransienceManager transience(&element, base::TimeDelta::FromSeconds(10));
-  EXPECT_EQ(element.visible(), false);
+  TransienceManager transience(&element, opacity_when_enabled,
+                               base::TimeDelta::FromSeconds(10));
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 
   transience.KickVisibilityIfEnabled();
-  EXPECT_EQ(element.visible(), false);
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 
   // Enable and disable, making sure the element appears and disappears.
   transience.SetEnabled(true);
-  EXPECT_EQ(element.visible(), true);
+  EXPECT_EQ(true, element.visible());
+  EXPECT_EQ(opacity_when_enabled, element.opacity());
   transience.SetEnabled(false);
-  EXPECT_EQ(element.visible(), false);
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 
   // Enable, and ensure that the element transiently disappears.
   transience.SetEnabled(true);
-  EXPECT_EQ(element.visible(), true);
+  EXPECT_EQ(true, element.visible());
+  EXPECT_EQ(opacity_when_enabled, element.opacity());
   task_runner_->FastForwardUntilNoTasksRemain();
-  EXPECT_EQ(element.visible(), false);
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 
   // Kick visibility, and ensure that the element transiently disappears.
   transience.KickVisibilityIfEnabled();
-  EXPECT_EQ(element.visible(), true);
+  EXPECT_EQ(true, element.visible());
+  EXPECT_EQ(opacity_when_enabled, element.opacity());
   task_runner_->FastForwardUntilNoTasksRemain();
-  EXPECT_EQ(element.visible(), false);
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 
   // Kick visibility, and ensure that ending visibility hides the element.
   transience.KickVisibilityIfEnabled();
-  EXPECT_EQ(element.visible(), true);
+  EXPECT_EQ(true, element.visible());
+  EXPECT_EQ(opacity_when_enabled, element.opacity());
   transience.EndVisibilityIfEnabled();
-  EXPECT_EQ(element.visible(), false);
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 
   // Kick visibility, and ensure that disabling hides the element.
   transience.KickVisibilityIfEnabled();
-  EXPECT_EQ(element.visible(), true);
+  EXPECT_EQ(true, element.visible());
+  EXPECT_EQ(opacity_when_enabled, element.opacity());
   transience.SetEnabled(false);
-  EXPECT_EQ(element.visible(), false);
+  EXPECT_EQ(false, element.visible());
+  EXPECT_EQ(0.0f, element.opacity());
 }
 
 }  // namespace vr

chrome/browser/vr/elements/transient_url_bar.cc

@@ -19,7 +19,7 @@ TransientUrlBar::TransientUrlBar(
     const base::Callback<void(UiUnsupportedMode)>& failure_callback)
     : TexturedElement(preferred_width),
       texture_(base::MakeUnique<UrlBarTexture>(true, failure_callback)),
-      transience_(this, timeout) {}
+      transience_(this, 1.0f, timeout) {}
 
 TransientUrlBar::~TransientUrlBar() = default;