Update activity indicator from a light bar to a point

ash/shelf/shelf_button.cc

Index: ash/shelf/shelf_button.cc
diff --git a/ash/shelf/shelf_button.cc b/ash/shelf/shelf_button.cc
index faf0b4e8c98b5f44a8e8942969528bf88b9bc5b2..f8dcef65320931047bf2a257837a6f62c9ca90f8 100644
--- a/ash/shelf/shelf_button.cc
+++ b/ash/shelf/shelf_button.cc
@@ -8,11 +8,14 @@
 
 #include "ash/ash_constants.h"
 #include "ash/ash_switches.h"
+#include "ash/material_design/material_design_controller.h"
 #include "ash/shelf/shelf.h"
+#include "ash/shelf/shelf_constants.h"
 #include "ash/shelf/shelf_view.h"
 #include "base/time/time.h"
 #include "grit/ash_resources.h"
 #include "skia/ext/image_operations.h"
+#include "third_party/skia/include/core/SkPaint.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/layer.h"
@@ -37,6 +40,9 @@ const int kIconPad = 5;
 const int kIconPadVertical = 6;
 const int kAttentionThrobDurationMS = 800;
 const int kMaxAnimationSeconds = 10;
+const int kIndicatorOffsetFromBottom = 2;
+const int kIndicatorRadius = 2;
+const int kIndicatorColor = SK_ColorWHITE;
 
 // Simple AnimationDelegate that owns a single ThrobAnimation instance to
 // keep all Draw Attention animations in sync.
@@ -486,8 +492,19 @@ void ShelfButton::UpdateBar() {
 
   if (bar_id != 0) {
     Shelf* shelf = shelf_view_->shelf();
-    ResourceBundle* rb = &ResourceBundle::GetSharedInstance();
-    gfx::ImageSkia image = *rb->GetImageNamed(bar_id).ToImageSkia();
+    gfx::ImageSkia image;
+    if (ash::MaterialDesignController::IsMaterial()) {
+      gfx::Size size = gfx::Size(kShelfButtonSize, kShelfSize);

[varkha, 2016/05/05 14:40:56]

nit: Simpler:
gfx::Size size(kShelfButtonSize, kShelfSize);

[yiyix, 2016/05/10 19:30:00]

Done.

+      // Chrome os is most common to run with 100% or 200% scale as default

[varkha, 2016/05/05 14:40:56]

nit: s/Chrome os/Chrome OS

[yiyix, 2016/05/10 19:30:00]

Done.

+      // setting, and users can zoom in to 200%. So image scale needs to be at
+      // least 4.

[varkha, 2016/05/05 14:40:56]

I suggest moving the scale to be a constant in anonymous namespace along with a
comment that could say something like:
// Canvas scale to ensures that the activity indicator is not pixelated even at
// the highest possible device scale factors.
const int kIndicatorCanvasScale = 5;

[yiyix, 2016/05/10 19:30:00]

I like your comment much more. It explains the purpose of this choice more
clearly.

+      gfx::Canvas canvas(size, 5 /* image scale*/, true /* is_opaque */);
+      PaintIndicatorOnCanvas(&canvas, size);
+      image = gfx::ImageSkia(canvas.ExtractImageRep());
+    } else {
+      ResourceBundle* rb = &ResourceBundle::GetSharedInstance();
+      image = *rb->GetImageNamed(bar_id).ToImageSkia();
+    }
     if (!shelf->IsHorizontalAlignment()) {
       image = gfx::ImageSkiaOperations::CreateRotatedImage(
           image, shelf->alignment() == wm::SHELF_ALIGNMENT_LEFT
@@ -503,8 +520,18 @@ void ShelfButton::UpdateBar() {
         views::ImageView::CENTER));
     bar_->SchedulePaint();
   }
-
   bar_->SetVisible(bar_id != 0 && state_ != STATE_NORMAL);
 }
 
+void ShelfButton::PaintIndicatorOnCanvas(gfx::Canvas* canvas,
+                                         const gfx::Size& size) {
+  SkPaint paint;
+  paint.setColor(kIndicatorColor);
+  paint.setFlags(SkPaint::kAntiAlias_Flag);
+  canvas->DrawCircle(
+      gfx::Point(size.width() / 2,
+                 size.height() - kIndicatorOffsetFromBottom - kIndicatorRadius),
+      kIndicatorRadius, paint);
+}
+
 }  // namespace ash