Theme suppliers: Avoid all Image copying.

chrome/browser/themes/theme_service.cc

Index: chrome/browser/themes/theme_service.cc
diff --git a/chrome/browser/themes/theme_service.cc b/chrome/browser/themes/theme_service.cc
index 11e8f1767a9b9aa2ed06f5019d260690fb9e900e..8f47278d09c158a334fdd99cacfe6d8db1b96336 100644
--- a/chrome/browser/themes/theme_service.cc
+++ b/chrome/browser/themes/theme_service.cc
@@ -672,7 +672,7 @@ SkColor ThemeService::GetSeparatorColor(SkColor tab_color,
 }
 
 gfx::ImageSkia* ThemeService::GetImageSkiaNamed(int id, bool incognito) const {
-  gfx::Image image = GetImageNamed(id, incognito);
+  const gfx::Image& image = GetImageNamed(id, incognito);
   if (image.IsEmpty())
     return nullptr;
   // TODO(pkotwicz): Remove this const cast.  The gfx::Image interface returns
@@ -744,7 +744,7 @@ base::RefCountedMemory* ThemeService::GetRawData(
   return data;
 }
 
-gfx::Image ThemeService::GetImageNamed(int id, bool incognito) const {
+const gfx::Image& ThemeService::GetImageNamed(int id, bool incognito) const {
   DCHECK(CalledOnValidThread());
 
   int adjusted_id = id;
@@ -755,14 +755,13 @@ gfx::Image ThemeService::GetImageNamed(int id, bool incognito) const {
       adjusted_id = IDR_THEME_FRAME_INCOGNITO_INACTIVE;
   }
 
-  gfx::Image image;
-  if (theme_supplier_)
-    image = theme_supplier_->GetImageNamed(adjusted_id);
-
-  if (image.IsEmpty())
-    image = rb_.GetNativeImageNamed(adjusted_id);
+  if (theme_supplier_) {
+    const gfx::Image& image = theme_supplier_->GetImageNamed(adjusted_id);
+    if (!image.IsEmpty())
+      return image;
+  }
 
-  return image;
+  return rb_.GetNativeImageNamed(adjusted_id);
 }
 
 void ThemeService::OnExtensionServiceReady() {