Fixed coverity defects pertaining to pass-by-value use where pass-by-reference is preferred

CID_COUNT=3
CID=(104210, 104215),104237,104238
BUG=
TEST=
TBR=jln,bolms,brettw

Review URL: https://chromiumcodereview.appspot.com/10825016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148437 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/shell_window_registry.cc

@@ -37,7 +37,7 @@ void ShellWindowRegistry::RemoveObserver(Observer* observer) {
 }
 
 ShellWindowRegistry::ShellWindowSet ShellWindowRegistry::GetShellWindowsForApp(
-    const std::string app_id) const {
+    const std::string& app_id) const {
   ShellWindowSet app_windows;
   for (ShellWindowSet::const_iterator i = shell_windows_.begin();
        i != shell_windows_.end(); ++i) {

chrome/browser/extensions/shell_window_registry.h

@@ -58,7 +58,7 @@ class ShellWindowRegistry : public ProfileKeyedService {
   void RemoveObserver(Observer* observer);
 
   // Returns a set of windows owned by the application identified by app_id.
-  ShellWindowSet GetShellWindowsForApp(const std::string app_id) const;
+  ShellWindowSet GetShellWindowsForApp(const std::string& app_id) const;
   const ShellWindowSet& shell_windows() const { return shell_windows_; }
 
   // Helper functions to find shell windows with particular attributes.

sandbox/linux/seccomp-bpf/sandbox_bpf.cc

@@ -249,7 +249,7 @@ bool Sandbox::isSingleThreaded(int proc_fd) {
   return true;
 }
 
-static bool isDenied(Sandbox::ErrorCode code) {
+static bool isDenied(const Sandbox::ErrorCode& code) {
   return (code & SECCOMP_RET_ACTION) == SECCOMP_RET_TRAP ||
          (code >= (SECCOMP_RET_ERRNO + 1) &&
           code <= (SECCOMP_RET_ERRNO + 4095));

sandbox/linux/seccomp-bpf/sandbox_bpf.h

@@ -325,7 +325,7 @@ class Sandbox {
   friend class Util;
   friend class Verifier;
   struct Range {
-    Range(uint32_t f, uint32_t t, ErrorCode e) :
+    Range(uint32_t f, uint32_t t, const ErrorCode& e) :
       from(f),
       to(t),
       err(e) {