[Extensions UI] Clean up extension icon generation

chrome/browser/extensions/api/extension_action/browser_action_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/extension_action/extension_action_api.h"
 #include "chrome/browser/extensions/browser_action_test_util.h"
 #include "chrome/browser/extensions/extension_action.h"
 #include "chrome/browser/extensions/extension_action_icon_factory.h"
 #include "chrome/browser/extensions/extension_action_manager.h"
@@ skipping 15 matching lines @@
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/notification_types.h"
 #include "extensions/browser/process_manager.h"
 #include "extensions/browser/test_extension_registry_observer.h"
 #include "extensions/common/feature_switch.h"
 #include "extensions/test/result_catcher.h"
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
+#include "ui/gfx/image/canvas_image_source.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/skia_util.h"
 
 using content::WebContents;
 
 namespace extensions {
 namespace {
 
+// An ImageSkia source that will do nothing (i.e., have a blank skia). We need

[Avi (use Gerrit), 2015/07/06 23:20:06]

... have a blank what?

You could totally just omit the parenthetical comment.

+// this because we need a blank canvas at a certain size, and that can't be done
+// by just using a null ImageSkia.
+class BlankImageSource : public gfx::CanvasImageSource {
+ public:
+  explicit BlankImageSource(const gfx::Size& size)
+     : gfx::CanvasImageSource(size, false) {}
+  ~BlankImageSource() override {}
+
+  void Draw(gfx::Canvas* canvas) override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BlankImageSource);
+};
+
 const char kEmptyImageDataError[] =
     "The imageData property must contain an ImageData object or dictionary "
     "of ImageData objects.";
 const char kEmptyPathError[] = "The path property must not be empty.";
 
-// Views implementation of browser action button will return icon whose
-// background will be set.
-gfx::ImageSkia AddBackgroundForViews(const gfx::ImageSkia& icon) {
+// Views platforms have the icon superimposed over a button's background.
+// Macs don't, but still need a 29x29-sized image (and the easiest way to do
+// that is to superimpose the icon over a blank background).
+gfx::ImageSkia AddBackground(const gfx::ImageSkia& icon) {
 #if !defined(OS_MACOSX)
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   gfx::ImageSkia bg = *rb.GetImageSkiaNamed(IDR_BROWSER_ACTION);
+#else
+  const gfx::Size size(29, 29);  // Size of browser actions buttons.
+  gfx::ImageSkia bg(new BlankImageSource(size), size);
+#endif
   return gfx::ImageSkiaOperations::CreateSuperimposedImage(bg, icon);
-#else
-  return icon;
-#endif
 }
 
 bool ImagesAreEqualAtScale(const gfx::ImageSkia& i1,
                            const gfx::ImageSkia& i2,
                            float scale) {
   SkBitmap bitmap1 = i1.GetRepresentation(scale).sk_bitmap();
   SkBitmap bitmap2 = i2.GetRepresentation(scale).sk_bitmap();
   return gfx::BitmapsAreEqual(bitmap1, bitmap2);
 }
 
@@ skipping 105 matching lines @@
 
   action_icon = icon_factory.GetIcon(0);
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_FALSE(action_icon.ToImageSkia()->HasRepresentation(2.0f));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon.ToImageSkia()),
+      ImagesAreEqualAtScale(AddBackground(*action_icon.ToImageSkia()),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             1.0f));
 
   // Tell the extension to update the icon using path.
   GetBrowserActionsBar()->Press(0);
   ASSERT_TRUE(catcher.GetNextResult());
 
   action_icon = icon_factory.GetIcon(0);
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_FALSE(
       action_icon.ToImageSkia()->HasRepresentation(2.0f));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon.ToImageSkia()),
+      ImagesAreEqualAtScale(AddBackground(*action_icon.ToImageSkia()),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             1.0f));
 
   // Tell the extension to update the icon using dictionary of ImageData
   // objects.
   GetBrowserActionsBar()->Press(0);
   ASSERT_TRUE(catcher.GetNextResult());
 
   action_icon = icon_factory.GetIcon(0);
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_TRUE(action_icon.ToImageSkia()->HasRepresentation(2.0f));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon.ToImageSkia()),
+      ImagesAreEqualAtScale(AddBackground(*action_icon.ToImageSkia()),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             1.0f));
 
   // Tell the extension to update the icon using dictionary of paths.
   GetBrowserActionsBar()->Press(0);
   ASSERT_TRUE(catcher.GetNextResult());
 
   action_icon = icon_factory.GetIcon(0);
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_TRUE(action_icon.ToImageSkia()->HasRepresentation(2.0f));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon.ToImageSkia()),
+      ImagesAreEqualAtScale(AddBackground(*action_icon.ToImageSkia()),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             1.0f));
 
   // Tell the extension to update the icon using dictionary of ImageData
   // objects, but setting only size 19.
   GetBrowserActionsBar()->Press(0);
   ASSERT_TRUE(catcher.GetNextResult());
 
   action_icon = icon_factory.GetIcon(0);
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_FALSE(action_icon.ToImageSkia()->HasRepresentation(2.0f));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon.ToImageSkia()),
+      ImagesAreEqualAtScale(AddBackground(*action_icon.ToImageSkia()),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             1.0f));
 
   // Tell the extension to update the icon using dictionary of paths, but
   // setting only size 19.
   GetBrowserActionsBar()->Press(0);
   ASSERT_TRUE(catcher.GetNextResult());
 
   action_icon = icon_factory.GetIcon(0);
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_FALSE(action_icon.ToImageSkia()->HasRepresentation(2.0f));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon.ToImageSkia()),
+      ImagesAreEqualAtScale(AddBackground(*action_icon.ToImageSkia()),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             1.0f));
 
   // Tell the extension to update the icon using dictionary of ImageData
   // objects, but setting only size 38.
   GetBrowserActionsBar()->Press(0);
   ASSERT_TRUE(catcher.GetNextResult());
 
   action_icon = icon_factory.GetIcon(0);
 
   const gfx::ImageSkia* action_icon_skia = action_icon.ToImageSkia();
 
   EXPECT_FALSE(action_icon_skia->HasRepresentation(1.0f));
   EXPECT_TRUE(action_icon_skia->HasRepresentation(2.0f));
 
   action_icon_current_id = action_icon.ToSkBitmap()->getGenerationID();
   EXPECT_GT(action_icon_current_id, action_icon_last_id);
   action_icon_last_id = action_icon_current_id;
 
   EXPECT_TRUE(gfx::BitmapsAreEqual(
       *action_icon.ToSkBitmap(),
       action_icon_skia->GetRepresentation(2.0f).sk_bitmap()));
 
   EXPECT_TRUE(
-      ImagesAreEqualAtScale(AddBackgroundForViews(*action_icon_skia),
+      ImagesAreEqualAtScale(AddBackground(*action_icon_skia),
                             *GetBrowserActionsBar()->GetIcon(0).ToImageSkia(),
                             2.0f));
 
   // Try setting icon with empty dictionary of ImageData objects.
   GetBrowserActionsBar()->Press(0);
   ASSERT_FALSE(catcher.GetNextResult());
   EXPECT_EQ(kEmptyImageDataError, catcher.message());
 
   // Try setting icon with empty dictionary of path objects.
   GetBrowserActionsBar()->Press(0);
@@ skipping 344 matching lines @@
   const std::string script =
       "window.domAutomationController.send(document.body.style."
       "backgroundColor);";
   std::string result;
   EXPECT_TRUE(content::ExecuteScriptAndExtractString(tab, script, &result));
   EXPECT_EQ(result, "red");
 }
 
 }  // namespace
 }  // namespace extensions