alternate ntp: implement searchbox api for instant overlay to adopt themes

chrome/common/instant_types.h

Index: chrome/common/instant_types.h
diff --git a/chrome/common/instant_types.h b/chrome/common/instant_types.h
index 627a565791f5e76828e00d17f4bb153dc564de7c..fd724ed347181b708aee068a6f23634a8bb26817 100644
--- a/chrome/common/instant_types.h
+++ b/chrome/common/instant_types.h
@@ -93,4 +93,37 @@ enum InstantShownReason {
   INSTANT_SHOWN_ZERO_SUGGESTIONS,
 };
 
+// Specifies information required for NTP instant overlay to adopt the browser's
+// theme.
+struct ThemeBackgroundInfo {
+  // The background color in RGBA format "rgba(R,G,B,A)" where R, G and B are
+  // between 0 and 255 inclusive, and A is a double between 0 and 1 inclusive.
+  // This is the CSS "background-color" format.
+  // Value is always valid.
+  string16 color_rgba;
+
+  // The image url of format
+  // "-webkit-image-set(url(chrome://theme/IDR_THEME_BACKGROUND?<theme_id>) 1x)"
+  // where <theme_id> is the id that identifies the theme.
+  // This is the CSS "background-image" format.
+  // Value is only valid if there's a custom theme background image.
+  string16 image_url;
+
+  // The image horizontal alignment: one of "left", "right", "center".
+  // This is the horizontal component of the CSS "background-position" format.
+  // Value is only valid if |image_url| is valid.
+  string16 image_horizontal_alignment;
+
+  // The image vertical alignment: one of "top", "bottom", "center".
+  // This is the vertical component of the CSS "background-position" format.
+  // Value is only valid if |image_url| is valid.
+  string16 image_vertical_alignment;
+
+  // The tiling of the image: one of "no-repeat", "repeat-x", "repeat-y",
+  // "repeat".
+  // This is the CSS "background-repeat" format.
+  // Value is only valid if |image_url| is valid.
+  string16 image_tiling;
+};
+
 #endif  // CHROME_COMMON_INSTANT_TYPES_H_