Paint tab-loading throbbers into a ui::Layer.

chrome/browser/ui/views/tabs/tab.cc

Index: chrome/browser/ui/views/tabs/tab.cc
diff --git a/chrome/browser/ui/views/tabs/tab.cc b/chrome/browser/ui/views/tabs/tab.cc
index 6d0d78ae342129de7cfe6e2eb8a11b18c20d701b..6a2f5cedc35ae5b6c0603285bda9756d213d6c72 100644
--- a/chrome/browser/ui/views/tabs/tab.cc
+++ b/chrome/browser/ui/views/tabs/tab.cc
@@ -137,6 +137,63 @@ const int kImmersiveLoadingStepCount = 32;
 const char kTabCloseButtonName[] = "TabCloseButton";
 const int kTabCloseButtonSize = 16;
 
+// Layer-backed view for updating a waiting or loading tab spinner.
+class ThrobberView : public views::View {
+ public:
+  ThrobberView(Tab* owner, const gfx::Rect& bounds) : owner_(owner) {
+    SetPaintToLayer(true);

[danakj, 2015/10/08 14:09:01]

Can you leave a comment that this paints to separate layer because it animates
its contents?

[tapted, 2015/10/09 06:39:02]

Done.

+    SetFillsBoundsOpaquely(false);
+    SetBoundsRect(bounds);
+    owner_->AddChildView(this);
+  }
+
+  // views::View:
+  void OnPaint(gfx::Canvas* canvas) override {
+    const TabRendererData::NetworkState state = owner_->data().network_state;
+    if (state == TabRendererData::NETWORK_STATE_NONE)
+      return;
+
+    const gfx::Rect bounds = GetLocalBounds();
+
+    // Paint network activity (aka throbber) animation frame.
+    ui::ThemeProvider* tp = owner_->GetThemeProvider();

[sky, 2015/10/08 15:52:23]

Do you really need owner_ here?

[tapted, 2015/10/09 06:39:02]

Whoops - removed.

+    if (state == TabRendererData::NETWORK_STATE_WAITING) {
+      if (waiting_start_time_ == base::TimeTicks())
+        waiting_start_time_ = base::TimeTicks::Now();
+
+      waiting_state_.elapsed_time =
+          base::TimeTicks::Now() - waiting_start_time_;
+      gfx::PaintThrobberWaiting(
+          canvas, bounds, tp->GetColor(ThemeProperties::COLOR_THROBBER_WAITING),
+          waiting_state_.elapsed_time);
+    } else {
+      if (loading_start_time_ == base::TimeTicks())
+        loading_start_time_ = base::TimeTicks::Now();
+
+      waiting_state_.color =
+          tp->GetColor(ThemeProperties::COLOR_THROBBER_WAITING);
+      gfx::PaintThrobberSpinningAfterWaiting(
+          canvas, bounds,
+          tp->GetColor(ThemeProperties::COLOR_THROBBER_SPINNING),
+          base::TimeTicks::Now() - loading_start_time_, &waiting_state_);
+    }
+  }
+
+ private:
+  Tab* owner_;  // Weak. Owns this.

[danakj, 2015/10/08 14:09:01]

"Owns this" can be a bit ambiguous. "Owns |this|"?

[tapted, 2015/10/09 06:39:02]

Done.

+
+  // The point in time when the tab icon was first painted in the waiting state.
+  base::TimeTicks waiting_start_time_;
+
+  // The point in time when the tab icon was first painted in the loading state.
+  base::TimeTicks loading_start_time_;
+
+  // Paint state for the throbber after the most recent waiting paint.
+  gfx::ThrobberWaitingState waiting_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(ThrobberView);
+};
+
 void DrawIconAtLocation(gfx::Canvas* canvas,
                         const gfx::ImageSkia& image,
                         int image_offset,
@@ -412,6 +469,7 @@ Tab::Tab(TabController* controller)
       favicon_hiding_offset_(0),
       immersive_loading_step_(0),
       should_display_crashed_favicon_(false),
+      throbber_(nullptr),
       media_indicator_button_(nullptr),
       close_button_(nullptr),
       title_(new views::Label()),
@@ -552,9 +610,8 @@ void Tab::UpdateLoadingAnimation(TabRendererData::NetworkState state) {
     return;
   }
 
-  TabRendererData::NetworkState old_state = data_.network_state;
   data_.network_state = state;
-  AdvanceLoadingAnimation(old_state, state);
+  AdvanceLoadingAnimation(state);
 }
 
 void Tab::StartPulse() {
@@ -787,6 +844,8 @@ void Tab::Layout() {
     favicon_bounds_.set_y(lb.y() + (lb.height() - gfx::kFaviconSize + 1) / 2);
     MaybeAdjustLeftForPinnedTab(&favicon_bounds_);
   }
+  if (throbber_)
+    throbber_->SetBoundsRect(favicon_bounds_);
 
   showing_close_button_ = ShouldShowCloseBox();
   if (showing_close_button_) {
@@ -1347,28 +1406,7 @@ void Tab::PaintIcon(gfx::Canvas* canvas) {
   bounds.set_x(GetMirroredXForRect(bounds));
 
   if (data().network_state != TabRendererData::NETWORK_STATE_NONE) {
-    // Paint network activity (aka throbber) animation frame.
-    ui::ThemeProvider* tp = GetThemeProvider();
-    if (data().network_state == TabRendererData::NETWORK_STATE_WAITING) {
-      if (waiting_start_time_ == base::TimeTicks())
-        waiting_start_time_ = base::TimeTicks::Now();
-
-      waiting_state_.elapsed_time =
-          base::TimeTicks::Now() - waiting_start_time_;
-      gfx::PaintThrobberWaiting(
-          canvas, bounds, tp->GetColor(ThemeProperties::COLOR_THROBBER_WAITING),
-          waiting_state_.elapsed_time);
-    } else {
-      if (loading_start_time_ == base::TimeTicks())
-        loading_start_time_ = base::TimeTicks::Now();
-
-      waiting_state_.color =
-          tp->GetColor(ThemeProperties::COLOR_THROBBER_WAITING);
-      gfx::PaintThrobberSpinningAfterWaiting(
-          canvas, bounds,
-          tp->GetColor(ThemeProperties::COLOR_THROBBER_SPINNING),
-          base::TimeTicks::Now() - loading_start_time_, &waiting_state_);
-    }
+    // Throbber will do its own painting.
   } else if (should_display_crashed_favicon_) {
     // Paint crash favicon.
     ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
@@ -1387,27 +1425,35 @@ void Tab::PaintIcon(gfx::Canvas* canvas) {
   }
 }
 
-void Tab::AdvanceLoadingAnimation(TabRendererData::NetworkState old_state,
-                                  TabRendererData::NetworkState state) {
-  if (state == TabRendererData::NETWORK_STATE_WAITING) {
-    // Waiting steps backwards.
-    immersive_loading_step_ =
-        (immersive_loading_step_ - 1 + kImmersiveLoadingStepCount) %
-            kImmersiveLoadingStepCount;
-  } else if (state == TabRendererData::NETWORK_STATE_LOADING) {
-    immersive_loading_step_ = (immersive_loading_step_ + 1) %
-        kImmersiveLoadingStepCount;
-  } else {
-    waiting_start_time_ = base::TimeTicks();
-    loading_start_time_ = base::TimeTicks();
-    waiting_state_ = gfx::ThrobberWaitingState();
-    immersive_loading_step_ = 0;
-  }
+void Tab::AdvanceLoadingAnimation(TabRendererData::NetworkState state) {
   if (controller_->IsImmersiveStyle()) {
+    if (state == TabRendererData::NETWORK_STATE_WAITING) {
+      // Waiting steps backwards.
+      immersive_loading_step_ =
+          (immersive_loading_step_ - 1 + kImmersiveLoadingStepCount) %
+              kImmersiveLoadingStepCount;
+    } else if (state == TabRendererData::NETWORK_STATE_LOADING) {
+      immersive_loading_step_ = (immersive_loading_step_ + 1) %
+          kImmersiveLoadingStepCount;
+    } else {
+      immersive_loading_step_ = 0;
+    }
+
     SchedulePaintInRect(GetImmersiveBarRect());
-  } else {
+    return;
+  }
+
+  const bool needs_throbber = state != TabRendererData::NETWORK_STATE_NONE;
+  if (needs_throbber && !throbber_) {
+    throbber_ = new ThrobberView(this, favicon_bounds_);
+    ScheduleIconPaint();  // Repaint the icon area to not show the icon.
+  } else if (!needs_throbber) {
+    delete throbber_;

[sky, 2015/10/08 15:52:23]

I would hide the throbber when you don't need it rather than destroying. Less
view shuffling.

[tapted, 2015/10/09 06:39:02]

Done.

+    throbber_ = nullptr;
     ScheduleIconPaint();
   }
+  if (throbber_)
+    throbber_->SchedulePaint();
 }
 
 int Tab::IconCapacity() const {