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..b51c05dfa7f5704a02f5bdb81aa711596dccec1f 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"
@@ -15,21 +16,60 @@
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/browser_thread.h"
 #include "googleurl/src/gurl.h"
+#include "ui/base/layout.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/theme_provider.h"
 
 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) {
+struct ScaleFactorMap {
+  const char* name;
+  ui::ScaleFactor scale_factor;
+};
+
+const ScaleFactorMap kScaleFactorMap[] = {
+  { "1x", ui::SCALE_FACTOR_100P },
+  { "2x", ui::SCALE_FACTOR_200P },
+};
+
+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,
+                              ui::ScaleFactor* scale_factor) {
+  // Our path may include cachebuster arguments, so trim them off.
+  std::string uncached_path = StripQueryParams(path);
+  if (scale_factor)
+    *scale_factor = ui::SCALE_FACTOR_100P;
+
+  // Detect and parse resource string ending in @<scale>x.
+  std::size_t pos = uncached_path.rfind('@');
+  if (pos != std::string::npos) {
+    if (scale_factor) {
+      for (size_t i = 0; i < arraysize(kScaleFactorMap); i++) {
+        if (uncached_path.compare(pos + 1, uncached_path.length() - pos - 1,
+            kScaleFactorMap[i].name) == 0) {
+          *scale_factor = kScaleFactorMap[i].scale_factor;
+        }
+      }
+    }
+    // Strip scale factor specification from path.
+    uncached_path = uncached_path.substr(0, pos);
+  }
+  return uncached_path;
+}
+
+}  // namespace
+
 ////////////////////////////////////////////////////////////////////////////////
 // ThemeSource, public:
 
@@ -46,8 +86,9 @@ 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.
+  ui::ScaleFactor scale_factor;
+  std::string uncached_path = ParsePathAndScale(path, &scale_factor);
 
   if (uncached_path == kNewTabCSSPath ||
       uncached_path == kNewIncognitoTabCSSPath) {
@@ -60,7 +101,7 @@ 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 +110,7 @@ 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 +122,7 @@ 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 +148,22 @@ bool ThemeSource::ShouldReplaceExistingSource() const {
 ////////////////////////////////////////////////////////////////////////////////
 // ThemeSource, private:
 
-void ThemeSource::SendThemeBitmap(int request_id, int resource_id) {
+void ThemeSource::SendThemeBitmap(int request_id,
+                                  int resource_id,
+                                  ui::ScaleFactor 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.LoadDataResourceBytes(resource_id, scale_factor));
   }
 }