Select theme resources from ResourceBundle at requested scale factor.

chrome/browser/ui/webui/theme_source.cc

Index: chrome/browser/ui/webui/theme_source.cc
diff --git a/chrome/browser/ui/webui/theme_source.cc b/chrome/browser/ui/webui/theme_source.cc
index 2c2a59b35ef102b3ff145593fbe81552a50441bb..95af046ebb772be30ea11cecf6fdfcdea2c2b209 100644
--- a/chrome/browser/ui/webui/theme_source.cc
+++ b/chrome/browser/ui/webui/theme_source.cc
@@ -6,6 +6,7 @@
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/message_loop.h"
+#include "base/string_number_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/resources_util.h"
 #include "chrome/browser/themes/theme_service.h"
@@ -20,16 +21,41 @@
 
 using content::BrowserThread;
 
+namespace {
+
 // use a resource map rather than hard-coded strings.
 static const char* kNewTabCSSPath = "css/new_tab_theme.css";
 static const char* kNewIncognitoTabCSSPath = "css/incognito_new_tab_theme.css";
 
-static std::string StripQueryParams(const std::string& path) {
+std::string StripQueryParams(const std::string& path) {
   GURL path_url = GURL(std::string(chrome::kChromeUIScheme) + "://" +
                        std::string(chrome::kChromeUIThemePath) + "/" + path);
   return path_url.path().substr(1);  // path() always includes a leading '/'.
 }
 
+std::string ParsePathAndScale(const std::string& path, float* scale_factor) {
+  // Our path may include cachebuster arguments, so trim them off.
+  std::string uncached_path = StripQueryParams(path);
+
+  // Detect and parse resource string ending in @<scale>x.
+  std::size_t pos = uncached_path.rfind('@');
+  if (pos != std::string::npos &&
+      uncached_path[uncached_path.length()-1] == 'x') {
+    double scale_d;
+    if (scale_factor &&
+        base::StringToDouble(
+            uncached_path.substr(pos + 1, uncached_path.length() - pos - 2),
+            &scale_d)) {
+      *scale_factor = scale_d;
+    }
+    // Strip scale factor specification from path.
+    uncached_path = uncached_path.substr(0, pos);
+  }
+  return uncached_path;
+}
+
+}  // namespace
+
 ////////////////////////////////////////////////////////////////////////////////
 // ThemeSource, public:
 
@@ -46,8 +72,9 @@ ThemeSource::~ThemeSource() {
 void ThemeSource::StartDataRequest(const std::string& path,
                                    bool is_incognito,
                                    int request_id) {
-  // Our path may include cachebuster arguments, so trim them off.
-  std::string uncached_path = StripQueryParams(path);
+  // Default scale factor if not specified.
+  float scale_factor = 1;
+  std::string uncached_path = ParsePathAndScale(path, &scale_factor);
 
   if (uncached_path == kNewTabCSSPath ||
       uncached_path == kNewIncognitoTabCSSPath) {
@@ -60,7 +87,7 @@ void ThemeSource::StartDataRequest(const std::string& path,
   } else {
     int resource_id = ResourcesUtil::GetThemeResourceId(uncached_path);
     if (resource_id != -1) {
-      SendThemeBitmap(request_id, resource_id);
+      SendThemeBitmap(request_id, resource_id, scale_factor);
       return;
     }
   }
@@ -69,7 +96,7 @@ void ThemeSource::StartDataRequest(const std::string& path,
 }
 
 std::string ThemeSource::GetMimeType(const std::string& path) const {
-  std::string uncached_path = StripQueryParams(path);
+  std::string uncached_path = ParsePathAndScale(path, NULL);
 
   if (uncached_path == kNewTabCSSPath ||
       uncached_path == kNewIncognitoTabCSSPath) {
@@ -81,7 +108,7 @@ std::string ThemeSource::GetMimeType(const std::string& path) const {
 
 MessageLoop* ThemeSource::MessageLoopForRequestPath(
     const std::string& path) const {
-  std::string uncached_path = StripQueryParams(path);
+  std::string uncached_path = ParsePathAndScale(path, NULL);
 
   if (uncached_path == kNewTabCSSPath ||
       uncached_path == kNewIncognitoTabCSSPath) {
@@ -107,18 +134,22 @@ bool ThemeSource::ShouldReplaceExistingSource() const {
 ////////////////////////////////////////////////////////////////////////////////
 // ThemeSource, private:
 
-void ThemeSource::SendThemeBitmap(int request_id, int resource_id) {
+void ThemeSource::SendThemeBitmap(int request_id,
+                                  int resource_id,
+                                  float scale_factor) {
   if (ThemeService::IsThemeableImage(resource_id)) {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     ui::ThemeProvider* tp = ThemeServiceFactory::GetForProfile(profile_);
     DCHECK(tp);
 
+    // TODO(flackr): Pass scale factor when fetching themeable images.
     scoped_refptr<base::RefCountedMemory> image_data(tp->GetRawData(
         resource_id));
     SendResponse(request_id, image_data);
   } else {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
     const ResourceBundle& rb = ResourceBundle::GetSharedInstance();
-    SendResponse(request_id, rb.LoadDataResourceBytes(resource_id));
+    SendResponse(request_id,
+                 rb.LoadImageResourceBytes(resource_id, scale_factor));
   }
 }