Mash: Show app icons in shelf based on the Widget's app icon

* Use the large icon from WidgetDelegate::GetWindowAppIcon().
* In the mojo app's NativeWidgetMus, serialize the icon's SkBitmap as a vector of bytes and set it as a shared window property.
* In the window manager, pass the serialized icon to any UserWindowObservers.
* In the system UI, deserialize the icon and use it on the shelf.
* Set an icon in task_viewer as a demonstration.

The window property serialization is handled by a custom TypeConverter for vector<uint8>, SkBitmap. In the future it would be nice to use the serialized form of the Skia Mojom struct skia.Bitmap, but that will require Mojo to generate a public API to read the serialized bytes.

Also fixed an issue where the app's primary widget and the window manager's non-client-frame widget would fight over window titles.

A screenshot of the shelf is attached to the bug.

BUG=595850
TEST=launch mash, run mojo:task_viewer, note QuickLaunch shelf icon is default but TaskViewer icon is a gear

Review URL: https://codereview.chromium.org/1824183002

Cr-Commit-Position: refs/heads/master@{#383312}

2 files changed, 39 insertions, 3 deletions

diff --git a/ash/mus/shelf_delegate_mus.cc b/ash/mus/shelf_delegate_mus.cc
index 510bb1b..5b06eda 100644
--- a/ash/mus/shelf_delegate_mus.cc
+++ b/ash/mus/shelf_delegate_mus.cc
@@ -19,6 +19,7 @@
 #include "mojo/shell/public/cpp/connector.h"
 #include "ui/aura/mus/mus_util.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/image/image_skia.h"
 #include "ui/resources/grit/ui_resources.h"
 #include "ui/views/mus/window_manager_connection.h"
 
@@ -78,6 +79,25 @@ class ShelfItemDelegateMus : public ShelfItemDelegate {
   DISALLOW_COPY_AND_ASSIGN(ShelfItemDelegateMus);
 };
 
+// Returns an icon image from a serialized SkBitmap, or the default shelf icon
+// image if the bitmap is empty. Assumes the bitmap is a 1x icon.
+// TODO(jamescook): Support other scale factors.
+gfx::ImageSkia GetShelfIconFromBitmap(
+    const mojo::Array<uint8_t>& serialized_bitmap) {
+  // Convert the data to an ImageSkia.
+  SkBitmap bitmap = mojo::ConvertTo<SkBitmap, const std::vector<uint8_t>>(
+      serialized_bitmap.storage());
+  gfx::ImageSkia icon_image;
+  if (!bitmap.isNull()) {
+    icon_image = gfx::ImageSkia::CreateFrom1xBitmap(bitmap);
+  } else {
+    // Use default icon.
+    ResourceBundle& rb = ResourceBundle::GetSharedInstance();
+    icon_image = *rb.GetImageSkiaNamed(IDR_DEFAULT_FAVICON);
+  }
+  return icon_image;
+}
+
 }  // namespace
 
 ShelfDelegateMus::ShelfDelegateMus(ShelfModel* model)
@@ -150,9 +170,7 @@ void ShelfDelegateMus::OnUserWindowAdded(
   ShelfItem item;
   item.type = TYPE_PLATFORM_APP;
   item.status = user_window->window_has_focus ? STATUS_ACTIVE : STATUS_RUNNING;
-  // TODO(msw): Support actual window icons.
-  ResourceBundle& rb = ResourceBundle::GetSharedInstance();
-  item.image = *rb.GetImageSkiaNamed(IDR_DEFAULT_FAVICON);
+  item.image = GetShelfIconFromBitmap(user_window->window_app_icon);
 
   ShelfID shelf_id = model_->next_id();
   window_id_to_shelf_id_.insert(
@@ -195,6 +213,22 @@ void ShelfDelegateMus::OnUserWindowTitleChanged(
   model_->Set(index, *iter);
 }
 
+void ShelfDelegateMus::OnUserWindowAppIconChanged(
+    uint32_t window_id,
+    mojo::Array<uint8_t> app_icon) {
+  // Find the shelf ID for this window.
+  DCHECK(window_id_to_shelf_id_.count(window_id));
+  ShelfID shelf_id = window_id_to_shelf_id_[window_id];
+  DCHECK_GT(shelf_id, 0);
+
+  // Update the icon in the ShelfItem.
+  int index = model_->ItemIndexByID(shelf_id);
+  DCHECK_GE(index, 0);
+  ShelfItem item = *model_->ItemByID(shelf_id);
+  item.image = GetShelfIconFromBitmap(app_icon);
+  model_->Set(index, item);
+}
+
 void ShelfDelegateMus::OnUserWindowFocusChanged(uint32_t window_id,
                                                 bool has_focus) {
   DCHECK(window_id_to_shelf_id_.count(window_id));
diff --git a/ash/mus/shelf_delegate_mus.h b/ash/mus/shelf_delegate_mus.h
index 47364fc..333a84d 100644
--- a/ash/mus/shelf_delegate_mus.h
+++ b/ash/mus/shelf_delegate_mus.h
@@ -41,6 +41,8 @@ class ShelfDelegateMus : public ShelfDelegate,
   void OnUserWindowRemoved(uint32_t window_id) override;
   void OnUserWindowTitleChanged(uint32_t window_id,
                                 const mojo::String& window_title) override;
+  void OnUserWindowAppIconChanged(uint32_t window_id,
+                                  mojo::Array<uint8_t> app_icon) override;
   void OnUserWindowFocusChanged(uint32_t window_id, bool has_focus) override;
 
   ShelfModel* model_;