Rewrite std::string("") to std::string(), Linux edition.

This patch was generated by running the empty_string clang tool
across the Chromium Linux compilation database. Implicitly or
explicitly constructing std::string() with a "" argument is
inefficient as the caller needs to emit extra instructions to
pass an argument, and the constructor needlessly copies a byte
into internal storage. Rewriting these instances to simply call
the default constructor appears to save ~14-18 kilobytes on an
optimized release build.

BUG=none

Review URL: https://codereview.chromium.org/13145003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193020 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 17 insertions, 9 deletions

diff --git a/chrome/browser/extensions/extension_browsertest.h b/chrome/browser/extensions/extension_browsertest.h
index 9d1203c..9d79f56 100644
--- a/chrome/browser/extensions/extension_browsertest.h
+++ b/chrome/browser/extensions/extension_browsertest.h
@@ -112,8 +112,8 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
   // you expect a failed upgrade.
   const extensions::Extension* InstallExtension(const base::FilePath& path,
                                                 int expected_change) {
-    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NONE,
-                                    expected_change);
+    return InstallOrUpdateExtension(
+        std::string(), path, INSTALL_UI_TYPE_NONE, expected_change);
   }
 
   // Same as above, but an install source other than Manifest::INTERNAL can be
@@ -122,8 +122,11 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
       const base::FilePath& path,
       int expected_change,
       extensions::Manifest::Location install_source) {
-    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NONE,
-                                    expected_change, install_source);
+    return InstallOrUpdateExtension(std::string(),
+                                    path,
+                                    INSTALL_UI_TYPE_NONE,
+                                    expected_change,
+                                    install_source);
   }
 
   // Installs extension as if it came from the Chrome Webstore.
@@ -144,22 +147,27 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
   const extensions::Extension* InstallExtensionWithUI(
       const base::FilePath& path,
       int expected_change) {
-    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NORMAL,
-                                    expected_change);
+    return InstallOrUpdateExtension(
+        std::string(), path, INSTALL_UI_TYPE_NORMAL, expected_change);
   }
 
   const extensions::Extension* InstallExtensionWithUIAutoConfirm(
       const base::FilePath& path,
       int expected_change,
       Browser* browser) {
-    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_AUTO_CONFIRM,
-                                    expected_change, browser, false);
+    return InstallOrUpdateExtension(std::string(),
+                                    path,
+                                    INSTALL_UI_TYPE_AUTO_CONFIRM,
+                                    expected_change,
+                                    browser,
+                                    false);
   }
 
   // Begins install process but simulates a user cancel.
   const extensions::Extension* StartInstallButCancel(
       const base::FilePath& path) {
-    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_CANCEL, 0);
+    return InstallOrUpdateExtension(
+        std::string(), path, INSTALL_UI_TYPE_CANCEL, 0);
   }
 
   void ReloadExtension(const std::string& extension_id);