[WebAssembly] Use "linker" as linker shortname.

[sbc100]

Summary

This is in line with other platforms.

Also, move the single statement methods into the header (also
in line with other platform).

[sunfish]

LGTM

cfe/trunk/lib/Driver/ToolChains/WebAssembly.h

 
 namespace clang {
 namespace driver {
 namespace tools {
 namespace wasm {
 
 class LLVM_LIBRARY_VISIBILITY Linker : public GnuTool {
 public:
-  explicit Linker(const ToolChain &TC);
-  bool isLinkJob() const override;
-  bool hasIntegratedCPP() const override;
+  explicit Linker(const ToolChain &TC)
+      : GnuTool("wasm::Linker", "linker", TC) {}
+  bool isLinkJob() const override { return true; }
+  bool hasIntegratedCPP() const override { return false; }
   std::string getLinkerPath(const llvm::opt::ArgList &Args) const;
   void ConstructJob(Compilation &C, const JobAction &JA,
                     const InputInfo &Output, const InputInfoList &Inputs,
                     const llvm::opt::ArgList &TCArgs,
                     const char *LinkingOutput) const override;
 };
 
 } // end namespace wasm

cfe/trunk/lib/Driver/ToolChains/WebAssembly.cpp

 #include "llvm/Option/ArgList.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
 using namespace clang;
 using namespace llvm::opt;
 
-wasm::Linker::Linker(const ToolChain &TC)
-    : GnuTool("wasm::Linker", "lld", TC) {}
-
 /// Following the conventions in https://wiki.debian.org/Multiarch/Tuples,
 /// we remove the vendor field to form the multiarch triple.
 static std::string getMultiarchTriple(const Driver &D,
                                       const llvm::Triple &TargetTriple,
                                       StringRef SysRoot) {
     return (TargetTriple.getArchName() + "-" +
             TargetTriple.getOSAndEnvironmentName()).str();
 }
 
-bool wasm::Linker::isLinkJob() const { return true; }
-
-bool wasm::Linker::hasIntegratedCPP() const { return false; }
-
 std::string wasm::Linker::getLinkerPath(const ArgList &Args) const {
   const ToolChain &ToolChain = getToolChain();
   if (const Arg* A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
     StringRef UseLinker = A->getValue();
     if (!UseLinker.empty()) {
       if (llvm::sys::path::is_absolute(UseLinker) &&
           llvm::sys::fs::can_execute(UseLinker))
         return UseLinker;