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

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=193020

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

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193040 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 5 insertions, 2 deletions

diff --git a/ppapi/shared_impl/ppb_audio_shared.cc b/ppapi/shared_impl/ppb_audio_shared.cc
index f275559..f6d0cac 100644
--- a/ppapi/shared_impl/ppb_audio_shared.cc
+++ b/ppapi/shared_impl/ppb_audio_shared.cc
@@ -80,8 +80,11 @@ void PPB_Audio_Shared::SetStreamInfo(
 
   if (!shared_memory_->Map(
           media::TotalSharedMemorySizeInBytes(shared_memory_size_))) {
-    PpapiGlobals::Get()->LogWithSource(instance, PP_LOGLEVEL_WARNING, "",
-      "Failed to map shared memory for PPB_Audio_Shared.");
+    PpapiGlobals::Get()->LogWithSource(
+        instance,
+        PP_LOGLEVEL_WARNING,
+        std::string(),
+        "Failed to map shared memory for PPB_Audio_Shared.");
   } else {
     audio_bus_ = media::AudioBus::WrapMemory(
         kChannels, sample_frame_count, shared_memory_->memory());