Cleanup: Make ExtensionIconSet::Get return a const std::string& rather than a

std::string.

R=mek@chromium.org

Review URL: https://codereview.chromium.org/448193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288156 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/sandboxed_unpacker.cc

@@ -694,9 +694,8 @@ bool SandboxedUnpacker::RewriteImageFiles(SkBitmap* install_icon) {
     }
   }
 
-  std::string install_icon_path = IconsInfo::GetIcons(extension_).Get(
-      extension_misc::EXTENSION_ICON_LARGE,
-      ExtensionIconSet::MATCH_BIGGER);
+  const std::string& install_icon_path = IconsInfo::GetIcons(extension_).Get(
+      extension_misc::EXTENSION_ICON_LARGE, ExtensionIconSet::MATCH_BIGGER);
 
   // Write our parsed images back to disk as well.
   for (size_t i = 0; i < images.size(); ++i) {

extensions/browser/extension_icon_image.cc

@@ -47,11 +47,9 @@ extensions::ExtensionResource GetExtensionIconResource(
     const ExtensionIconSet& icons,
     int size,
     ExtensionIconSet::MatchType match_type) {
-  std::string path = icons.Get(size, match_type);
-  if (path.empty())
-    return extensions::ExtensionResource();
-
-  return extension->GetResource(path);
+  const std::string& path = icons.Get(size, match_type);
+  return path.empty() ? extensions::ExtensionResource()
+                      : extension->GetResource(path);
 }
 
 class BlankImageSource : public gfx::CanvasImageSource {

extensions/common/extension_icon_set.cc

@@ -5,6 +5,7 @@
 #include "extensions/common/extension_icon_set.h"
 
 #include "base/logging.h"
+#include "base/strings/string_util.h"
 
 ExtensionIconSet::ExtensionIconSet() {}
 
@@ -19,12 +20,12 @@ void ExtensionIconSet::Add(int size, const std::string& path) {
   map_[size] = path;
 }
 
-std::string ExtensionIconSet::Get(int size, MatchType match_type) const {
+const std::string& ExtensionIconSet::Get(int size, MatchType match_type) const {
   // The searches for MATCH_BIGGER and MATCH_SMALLER below rely on the fact that
   // std::map is sorted. This is per the spec, so it should be safe to rely on.
   if (match_type == MATCH_EXACTLY) {
     IconMap::const_iterator result = map_.find(size);
-    return result == map_.end() ? std::string() : result->second;
+    return result == map_.end() ? base::EmptyString() : result->second;
   } else if (match_type == MATCH_SMALLER) {
     IconMap::const_reverse_iterator result = map_.rend();
     for (IconMap::const_reverse_iterator iter = map_.rbegin();
@@ -34,7 +35,7 @@ std::string ExtensionIconSet::Get(int size, MatchType match_type) const {
         break;
       }
     }
-    return result == map_.rend() ? std::string() : result->second;
+    return result == map_.rend() ? base::EmptyString() : result->second;
   } else {
     DCHECK(match_type == MATCH_BIGGER);
     IconMap::const_iterator result = map_.end();
@@ -45,7 +46,7 @@ std::string ExtensionIconSet::Get(int size, MatchType match_type) const {
         break;
       }
     }
-    return result == map_.end() ? std::string() : result->second;
+    return result == map_.end() ? base::EmptyString() : result->second;
   }
 }
 

extensions/common/extension_icon_set.h

@@ -37,7 +37,7 @@ class ExtensionIconSet {
 
   // Gets path value of the icon found when searching for |size| using
   // |mathc_type|.
-  std::string Get(int size, MatchType match_type) const;
+  const std::string& Get(int size, MatchType match_type) const;
 
   // Returns true iff the set contains the specified path.
   bool ContainsPath(const std::string& path) const;

extensions/common/manifest_handlers/icons_handler.cc

@@ -37,7 +37,7 @@ ExtensionResource IconsInfo::GetIconResource(
     const Extension* extension,
     int size,
     ExtensionIconSet::MatchType match_type) {
-  std::string path = GetIcons(extension).Get(size, match_type);
+  const std::string& path = GetIcons(extension).Get(size, match_type);
   return path.empty() ? ExtensionResource() : extension->GetResource(path);
 }
 
@@ -45,7 +45,7 @@ ExtensionResource IconsInfo::GetIconResource(
 GURL IconsInfo::GetIconURL(const Extension* extension,
                            int size,
                            ExtensionIconSet::MatchType match_type) {
-  std::string path = GetIcons(extension).Get(size, match_type);
+  const std::string& path = GetIcons(extension).Get(size, match_type);
   return path.empty() ? GURL() : extension->GetResourceURL(path);
 }