[clangd] Pass file when possible to resolve URI.

[hokein]

Summary

Some URI scheme needs the hint path to do a correct resolution, we pass
one of the open files as hint path.

This is not perfect, and it might not work for opening files across
project, but it would fix a bug with our internal scheme.

in the long run, removing URIs from all the index internals is a more proper fix.

clang-tools-extra/clangd/index/MemIndex.cpp

for (const SymbolID &Subject : Req.Subjects) {
     }
     lookup(LookupReq, [&](const Symbol &Object) { Callback(Subject, Object); });
   }
 }
 
 llvm::unique_function<IndexContents(llvm::StringRef) const>
 MemIndex::indexedFiles() const {
   return [this](llvm::StringRef FileURI) {
-    auto Path = URI::resolve(FileURI);
+    if (Files.empty())
+      return IndexContents::None;
+    auto Path = URI::resolve(FileURI, Files.begin()->first());
     if (!Path) {
-      llvm::consumeError(Path.takeError());
+      vlog("Failed to resolve the URI {0} : {1}", FileURI, Path.takeError());
       return IndexContents::None;
     }
     return Files.contains(*Path) ? IdxContents : IndexContents::None;
   };
 }
 
 size_t MemIndex::estimateMemoryUsage() const {
   return Index.getMemorySize() + Refs.getMemorySize() +
          Relations.getMemorySize() + BackingDataSize;
 }
 
 } // namespace clangd
 } // namespace clang

clang-tools-extra/clangd/index/dex/Dex.cpp

for (const SymbolID &Subject : Req.Subjects) {
     }
     lookup(LookupReq, [&](const Symbol &Object) { Callback(Subject, Object); });
   }
 }
 
 llvm::unique_function<IndexContents(llvm::StringRef) const>
 Dex::indexedFiles() const {
   return [this](llvm::StringRef FileURI) {
-    auto Path = URI::resolve(FileURI);
+    if (Files.empty())
+      return IndexContents::None;
+    auto Path = URI::resolve(FileURI, Files.begin()->first());
     if (!Path) {
-      llvm::consumeError(Path.takeError());
+      vlog("Failed to resolve the URI {0} : {1}", FileURI, Path.takeError());
       return IndexContents::None;
     }
     return Files.contains(*Path) ? IdxContents : IndexContents::None;
   };
 }
 
 size_t Dex::estimateMemoryUsage() const {
   size_t Bytes = Symbols.size() * sizeof(const Symbol *);