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, 16 insertions, 21 deletions

diff --git a/chrome/renderer/plugins/plugin_uma_unittest.cc b/chrome/renderer/plugins/plugin_uma_unittest.cc
index 99e6271..3b1950c 100644
--- a/chrome/renderer/plugins/plugin_uma_unittest.cc
+++ b/chrome/renderer/plugins/plugin_uma_unittest.cc
@@ -118,9 +118,8 @@ TEST_F(PluginUMATest, WidevineCdm) {
 }
 
 TEST_F(PluginUMATest, BySrcExtension) {
-  ExpectPluginType(PluginUMAReporter::QUICKTIME,
-                   "",
-                   GURL("file://file.mov"));
+  ExpectPluginType(
+      PluginUMAReporter::QUICKTIME, std::string(), GURL("file://file.mov"));
 
   // When plugin's mime type is given, we don't check extension.
   ExpectPluginType(PluginUMAReporter::UNSUPPORTED_MIMETYPE,
@@ -128,40 +127,36 @@ TEST_F(PluginUMATest, BySrcExtension) {
                    GURL("http://file.mov"));
 
   ExpectPluginType(PluginUMAReporter::WINDOWS_MEDIA_PLAYER,
-                   "",
+                   std::string(),
                    GURL("file://file.asx"));
-  ExpectPluginType(PluginUMAReporter::REALPLAYER,
-                   "",
-                   GURL("file://file.rm"));
+  ExpectPluginType(
+      PluginUMAReporter::REALPLAYER, std::string(), GURL("file://file.rm"));
   ExpectPluginType(PluginUMAReporter::QUICKTIME,
-                   "",
+                   std::string(),
                    GURL("http://aaa/file.mov?x=aaaa&y=b#c"));
   ExpectPluginType(PluginUMAReporter::QUICKTIME,
-                   "",
+                   std::string(),
                    GURL("http://file.mov?x=aaaa&y=b#c"));
   ExpectPluginType(PluginUMAReporter::SHOCKWAVE_FLASH,
-                   "",
+                   std::string(),
                    GURL("http://file.swf?x=aaaa&y=b#c"));
   ExpectPluginType(PluginUMAReporter::SHOCKWAVE_FLASH,
-                   "",
+                   std::string(),
                    GURL("http://file.spl?x=aaaa&y=b#c"));
 
   ExpectPluginType(PluginUMAReporter::UNSUPPORTED_EXTENSION,
-                   "",
+                   std::string(),
                    GURL("http://file.unknown_extension"));
-  ExpectPluginType(PluginUMAReporter::UNSUPPORTED_EXTENSION,
-                   "",
-                   GURL("http://"));
-  ExpectPluginType(PluginUMAReporter::UNSUPPORTED_EXTENSION,
-                   "",
-                   GURL("mov"));
+  ExpectPluginType(
+      PluginUMAReporter::UNSUPPORTED_EXTENSION, std::string(), GURL("http://"));
+  ExpectPluginType(
+      PluginUMAReporter::UNSUPPORTED_EXTENSION, std::string(), GURL("mov"));
 }
 
 TEST_F(PluginUMATest, CaseSensitivity) {
   ExpectPluginType(PluginUMAReporter::QUICKTIME,
                    "video/QUICKTIME",
                    GURL("http://file.aaa"));
-  ExpectPluginType(PluginUMAReporter::QUICKTIME,
-                   "",
-                   GURL("http://file.MoV"));
+  ExpectPluginType(
+      PluginUMAReporter::QUICKTIME, std::string(), GURL("http://file.MoV"));
 }