Bug 1336243 - Fix a regression from bug 1324617 in launching the browser post-install. r=agashlin

Bug 1324617 changed the name of the registry path that was being used to find
the new installation to launch, but forgot to update that function. This patch
switches to a more direct method of getting the right path to launch.

MozReview-Commit-ID: Hexhj9y4ixc

--HG--
extra : rebase_source : 8937bb4c2182f609388e8f972d002fed35b9443a

browser/installer/windows/nsis/installer.nsi

@@ -838,16 +838,10 @@ Function LaunchApp
 FunctionEnd
 
 Function LaunchAppFromElevatedProcess
-  ; Find the installation directory when launching using GetFunctionAddress
-  ; from an elevated installer since $INSTDIR will not be set in this installer
-  ${StrFilter} "${FileMainEXE}" "+" "" "" $R9
-  ReadRegStr $0 HKLM "Software\Clients\StartMenuInternet\$R9\DefaultIcon" ""
-  ${GetPathFromString} "$0" $0
-  ${GetParent} "$0" $1
   ; Set our current working directory to the application's install directory
   ; otherwise the 7-Zip temp directory will be in use and won't be deleted.
-  SetOutPath "$1"
+  SetOutPath "$INSTDIR"
-  Exec "$\"$0$\""
+  Exec "$\"$INSTDIR\${FileMainEXE}$\""
 FunctionEnd
 
 ################################################################################

browser/installer/windows/nsis/stub.nsi

@@ -2065,15 +2065,9 @@ Function LaunchApp
 FunctionEnd
 
 Function LaunchAppFromElevatedProcess
-  ; Find the installation directory when launching using GetFunctionAddress
-  ; from an elevated installer since $INSTDIR will not be set in this installer
-  ${StrFilter} "${FileMainEXE}" "+" "" "" $R9
-  ReadRegStr $0 HKLM "Software\Clients\StartMenuInternet\$R9\DefaultIcon" ""
-  ${GetPathFromString} "$0" $0
   ; Set the current working directory to the installation directory
-  ${GetParent} "$0" $1
+  SetOutPath "$INSTDIR"
-  SetOutPath "$1"
+  Exec "$\"$INSTDIR\${FileMainEXE}$\""
-  Exec "$\"$0$\""
 FunctionEnd
 
 Function CopyPostSigningData