Add an accordian effect to NTP.

chrome/browser/dom_ui/ntp_resource_cache.cc

 // Copyright (c) 2009 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 "chrome/browser/dom_ui/ntp_resource_cache.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "app/animation.h"
@@ skipping 385 matching lines @@
   SkColor color_section_text =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_TEXT);
   SkColor color_section_link =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_LINK);
   SkColor color_section_link_underline =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_LINK_UNDERLINE);
   SkColor color_section_header_text =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_HEADER_TEXT);
   SkColor color_section_header_text_hover =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_HEADER_TEXT_HOVER);
+  SkColor color_section_header_rule =
+      tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_HEADER_RULE);
+  SkColor color_section_header_rule_light =
+      tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION_HEADER_RULE_LIGHT);
 
   SkColor color_header =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_HEADER);
   // Generate a lighter color for the header gradients.
   color_utils::HSL header_lighter;
   color_utils::SkColorToHSL(color_header, &header_lighter);
   header_lighter.l += (1 - header_lighter.l) * 0.33;
   SkColor color_header_gradient_light =
       color_utils::HSLToSkColor(header_lighter, SkColorGetA(color_header));
 
   // Generate section border color from the header color. See
   // BookmarkBarView::Paint for how we do this for the bookmark bar
   // borders.
   SkColor color_section_border =
       SkColorSetARGB(80,
                      SkColorGetR(color_header),
                      SkColorGetG(color_header),
                      SkColorGetB(color_header));
 
   // Generate the replacements.
   std::vector<std::string> subst;
   // A second list of replacements, each of which must be in $$x format,
   // where x is a digit from 1-9.
   std::vector<std::string> subst2;
+  std::vector<std::string> subst3;
 
   // Cache-buster for background.
   subst.push_back(
       profile_->GetPrefs()->GetString(prefs::kCurrentThemeID));  // $1
 
   // Colors.
   subst.push_back(SkColorToRGBAString(color_background));  // $2
   subst.push_back(GetNewTabBackgroundCSS(tp, false));  // $3
   subst.push_back(GetNewTabBackgroundCSS(tp, true));  // $4
   subst.push_back(GetNewTabBackgroundTilingCSS(tp));  // $5
   subst.push_back(SkColorToRGBAString(color_header));  // $6
   subst.push_back(SkColorToRGBAString(color_header_gradient_light));  // $7
   subst.push_back(SkColorToRGBAString(color_text));  // $8
   subst.push_back(SkColorToRGBAString(color_link));  // $9
 
   subst2.push_back(SkColorToRGBAString(color_section));  // $$1
   subst2.push_back(SkColorToRGBAString(color_section_border));  // $$2
   subst2.push_back(SkColorToRGBAString(color_section_text));  // $$3
   subst2.push_back(SkColorToRGBAString(color_section_link));  // $$4
   subst2.push_back(
       tp->HasCustomImage(IDR_THEME_NTP_ATTRIBUTION) ? "block" : "none");  // $$5
   subst2.push_back(SkColorToRGBAString(color_link_underline));  // $$6
   subst2.push_back(SkColorToRGBAString(color_section_link_underline));  // $$7
   subst2.push_back(SkColorToRGBAString(color_section_header_text)); // $$8
   subst2.push_back(SkColorToRGBAString(
       color_section_header_text_hover)); // $$9
 
+  // A fully transparent version of the background color --- used for gradients.
+  subst3.push_back(SkColorToRGBAString(
+      SkColorSetA(color_background, 0)));  // $$$1
+
+  // TODO(aa): It seems we could generate sensible defaults for all these colors
+  // for better backward compat with old themes.
+  subst3.push_back(SkColorToRGBAString(color_section_header_rule));  // $$$2
+  subst3.push_back(SkColorToRGBAString(
+      color_section_header_rule_light));  // $$$3
+
   // Get our template.
   static const base::StringPiece new_tab_theme_css(
       ResourceBundle::GetSharedInstance().GetRawDataResource(
       IDR_NEW_TAB_THEME_CSS));
 
   // Create the string from our template and the replacements.
   std::string css_string;
   css_string = ReplaceStringPlaceholders(new_tab_theme_css, subst, NULL);
   css_string = ReplaceStringPlaceholders(css_string, subst2, NULL);
+  css_string = ReplaceStringPlaceholders(css_string, subst3, NULL);
 
   new_tab_css_ = new RefCountedBytes;
   new_tab_css_->data.resize(css_string.size());
   std::copy(css_string.begin(), css_string.end(),
             new_tab_css_->data.begin());
 }