arc: Support more types of notifications.

ui/message_center/message_center_style.h

Index: ui/message_center/message_center_style.h
diff --git a/ui/message_center/message_center_style.h b/ui/message_center/message_center_style.h
index d8187269dcb11702ea2336a729164099d7a71384..fb980a351f491e5851d74e336472128c60d75d9f 100644
--- a/ui/message_center/message_center_style.h
+++ b/ui/message_center/message_center_style.h
@@ -78,7 +78,8 @@ const int kMessageLineHeight = 18;         // In DIPs.
 
 // Colors.
 extern const SkColor kNotificationBackgroundColor; // Background of the card.
-extern const SkColor kImageBackgroundColor;        // Background of the image.
+MESSAGE_CENTER_EXPORT extern const SkColor
+    kImageBackgroundColor;        // Background of the image.

[dcheng, 2016/04/27 01:04:09]

I'd suggest moving this comment to before this line to avoid this funny
indenting.

(Also, not necessary for this CL, but why don't we just inline the colors in the
header file? SkColor is just a uint32. It'll reduce the clunkiness of having to
use the EXPORT macros)

[yoshiki, 2016/04/28 18:43:21]

Done.
Let me fix these extern'd SkColors in a separated patch.

 extern const SkColor kIconBackgroundColor;         // Used behind icons smaller
                                                    // than the icon view.
 extern const SkColor kRegularTextColor;            // Title, message, ...
@@ -98,7 +99,8 @@ MESSAGE_CENTER_EXPORT gfx::Size GetImageSizeForContainerSize(
     const gfx::Size& image_size);
 
 extern const int kNotificationMaximumImageHeight;  // For image notifications.
-extern const size_t kNotificationMaximumItems;     // For list notifications.
+MESSAGE_CENTER_EXPORT extern const size_t
+    kNotificationMaximumItems;     // For list notifications.
 
 // Timing.
 extern const int kAutocloseDefaultDelaySeconds;