Improve New Tab Page load performance

chrome/browser/dom_ui/dom_ui_theme_source.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/dom_ui_theme_source.h"
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "app/theme_provider.h"
 #include "base/gfx/png_encoder.h"
@@ skipping 32 matching lines @@
                        std::string(chrome::kChromeUIThemePath) + "/" + path);
   return path_url.path().substr(1);  // path() always includes a leading '/'.
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // DOMUIThemeSource, public:
 
 DOMUIThemeSource::DOMUIThemeSource(Profile* profile)
     : DataSource(chrome::kChromeUIThemePath, MessageLoop::current()),
       profile_(profile) {
+  InitNewTabCSS();
+  InitNewIncognitoTabCSS();
 }
 
 void DOMUIThemeSource::StartDataRequest(const std::string& path,
                                         int request_id) {
   // Our path may include cachebuster arguments, so trim them off.
   std::string uncached_path = StripQueryParams(path);
 
-  if (strcmp(uncached_path.c_str(), kNewTabCSSPath) == 0) {
-    SendNewTabCSS(request_id);
+  if (uncached_path == kNewTabCSSPath) {
+    SendNewTabCSS(request_id, new_tab_css_);
     return;
-  } else if (strcmp(uncached_path.c_str(), kNewIncognitoTabCSSPath) == 0) {
-    SendNewIncognitoTabCSS(request_id);
+  } else if (uncached_path == kNewIncognitoTabCSSPath) {
+    SendNewTabCSS(request_id, new_incognito_tab_css_);
     return;
   } else {
     int resource_id = ThemeResourcesUtil::GetId(uncached_path);
     if (resource_id != -1) {
       SendThemeBitmap(request_id, resource_id);
       return;
     }
   }
   // We don't have any data to send back.
   SendResponse(request_id, NULL);
 }
 
 std::string DOMUIThemeSource::GetMimeType(const std::string& path) const {
   std::string uncached_path = StripQueryParams(path);
 
-  if (strcmp(uncached_path.c_str(), kNewTabCSSPath) == 0 ||
-      strcmp(uncached_path.c_str(), kNewIncognitoTabCSSPath) == 0)
+  if (uncached_path == kNewTabCSSPath ||
+      uncached_path == kNewIncognitoTabCSSPath) {
     return "text/css";
+  }
+
   return "image/png";
 }
 
 void DOMUIThemeSource::SendResponse(int request_id, RefCountedBytes* data) {
   ChromeURLDataManager::DataSource::SendResponse(request_id, data);
 }
 
+MessageLoop* DOMUIThemeSource::MessageLoopForRequestPath(
+    const std::string& path) const {
+  std::string uncached_path = StripQueryParams(path);
+
+  if (uncached_path == kNewTabCSSPath ||
+      uncached_path == kNewIncognitoTabCSSPath) {
+    // All of the operations that need to be on the UI thread for these
+    // requests are performed in InitNewTabCSS and InitNewIncognitoTabCSS,
+    // called by the constructor.  It is safe to call StartDataRequest for
+    // these resources from any thread, so return NULL.
+    return NULL;
+  }
+
+  // Superclass
+  return DataSource::MessageLoopForRequestPath(path);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // DOMUIThemeSource, private:
 
-void DOMUIThemeSource::SendNewTabCSS(int request_id) {
+void DOMUIThemeSource::InitNewTabCSS() {
   ThemeProvider* tp = profile_->GetThemeProvider();
   DCHECK(tp);
 
   // Get our theme colors
   SkColor color_background =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_BACKGROUND);
   SkColor color_text = tp->GetColor(BrowserThemeProvider::COLOR_NTP_TEXT);
   SkColor color_link = tp->GetColor(BrowserThemeProvider::COLOR_NTP_LINK);
   SkColor color_section =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_SECTION);
@@ skipping 50 matching lines @@
 
   // Get our template.
   static const StringPiece new_tab_theme_css(
       ResourceBundle::GetSharedInstance().GetRawDataResource(
       IDR_NEW_TAB_THEME_CSS));
 
   // Create the string from our template and the replacements.
   string16 format_string = ASCIIToUTF16(new_tab_theme_css.as_string());
   const std::string css_string = UTF16ToASCII(ReplaceStringPlaceholders(
       format_string, subst, NULL));
-  const std::string css_string2 =  UTF16ToASCII(ReplaceStringPlaceholders(
+  new_tab_css_ = UTF16ToASCII(ReplaceStringPlaceholders(
       ASCIIToUTF16(css_string), subst2, NULL));
-
-  // Convert to a format appropriate for sending.
-  scoped_refptr<RefCountedBytes> css_bytes(new RefCountedBytes);
-  css_bytes->data.resize(css_string2.size());
-  std::copy(css_string2.begin(), css_string2.end(), css_bytes->data.begin());
-
-  // Send.
-  SendResponse(request_id, css_bytes);
 }
 
-void DOMUIThemeSource::SendNewIncognitoTabCSS(int request_id) {
+void DOMUIThemeSource::InitNewIncognitoTabCSS() {
   ThemeProvider* tp = profile_->GetThemeProvider();
   DCHECK(tp);
 
   // Get our theme colors
   SkColor color_background =
       tp->GetColor(BrowserThemeProvider::COLOR_NTP_BACKGROUND);
 
   // Generate the replacements.
   std::vector<string16> subst;
 
   // Cache-buster for background.
   subst.push_back(WideToUTF16(
       profile_->GetPrefs()->GetString(prefs::kCurrentThemeID)));  // $1
 
   // Colors.
   subst.push_back(SkColorToRGBAString(color_background));  // $2
   subst.push_back(UTF8ToUTF16(GetNewTabBackgroundCSS(false)));  // $3
   subst.push_back(UTF8ToUTF16(GetNewTabBackgroundCSS(true)));  // $4
   subst.push_back(UTF8ToUTF16(GetNewTabBackgroundTilingCSS()));  // $5
 
   // Get our template.
   static const StringPiece new_tab_theme_css(
       ResourceBundle::GetSharedInstance().GetRawDataResource(
       IDR_NEW_INCOGNITO_TAB_THEME_CSS));
 
   // Create the string from our template and the replacements.
   string16 format_string = ASCIIToUTF16(new_tab_theme_css.as_string());
-  const std::string css_string = UTF16ToASCII(ReplaceStringPlaceholders(
+  new_incognito_tab_css_ = UTF16ToASCII(ReplaceStringPlaceholders(
       format_string, subst, NULL));
+}
 
+void DOMUIThemeSource::SendNewTabCSS(int request_id,
+                                     const std::string& css_string) {
   // Convert to a format appropriate for sending.
   scoped_refptr<RefCountedBytes> css_bytes(new RefCountedBytes);
   css_bytes->data.resize(css_string.size());
   std::copy(css_string.begin(), css_string.end(), css_bytes->data.begin());
 
   // Send.
   SendResponse(request_id, css_bytes);
 }
 
 void DOMUIThemeSource::SendThemeBitmap(int request_id, int resource_id) {
@@ skipping 44 matching lines @@
   return BrowserThemeProvider::AlignmentToString(alignment);
 }
 
 std::string DOMUIThemeSource::GetNewTabBackgroundTilingCSS() {
   int repeat_mode;
   profile_->GetThemeProvider()->GetDisplayProperty(
       BrowserThemeProvider::NTP_BACKGROUND_TILING, &repeat_mode);
   return BrowserThemeProvider::TilingToString(repeat_mode);
 }