Replace HostInfo::GetLLDBPath with specific functions

Summary:
Instead of a function taking an enum value determining which path to
return, we now have a suite of functions, each returning a single path
kind. This makes it easy to move the python-path function into a
specific plugin in a follow-up commit.

All the users of GetLLDBPath were converted to call specific functions
instead. Most of them were hard-coding the enum value anyway, so this
conversion was simple. The only exception was SBHostOS, which I've
changed to use a switch on the incoming enum value.

Reviewers: clayborg, zturner

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D48272

llvm-svn: 335052
diff --git a/lldb/source/Core/Debugger.cpp b/lldb/source/Core/Debugger.cpp
index 9d68d84..6cb8526 100644
--- a/lldb/source/Core/Debugger.cpp
+++ b/lldb/source/Core/Debugger.cpp
@@ -646,19 +646,18 @@
 }
 
 void Debugger::InstanceInitialize() {
-  FileSpec dir_spec;
   const bool find_directories = true;
   const bool find_files = true;
   const bool find_other = true;
   char dir_path[PATH_MAX];
-  if (HostInfo::GetLLDBPath(ePathTypeLLDBSystemPlugins, dir_spec)) {
+  if (FileSpec dir_spec = HostInfo::GetSystemPluginDir()) {
     if (dir_spec.Exists() && dir_spec.GetPath(dir_path, sizeof(dir_path))) {
       FileSpec::EnumerateDirectory(dir_path, find_directories, find_files,
                                    find_other, LoadPluginCallback, this);
     }
   }
 
-  if (HostInfo::GetLLDBPath(ePathTypeLLDBUserPlugins, dir_spec)) {
+  if (FileSpec dir_spec = HostInfo::GetUserPluginDir()) {
     if (dir_spec.Exists() && dir_spec.GetPath(dir_path, sizeof(dir_path))) {
       FileSpec::EnumerateDirectory(dir_path, find_directories, find_files,
                                    find_other, LoadPluginCallback, this);