Don't return true from GetTrackedFileData() if no data has been loaded

The file might be being tracked but wasn't loaded from the embedded files in the capture i.e. it hasn't been physically embedded yet.

renderdoc/core/core.cpp

@@ -2455,8 +2455,9 @@ bool RenderDoc::GetTrackedFileData(const rdcstr &nickname, bytebuf &data) const
   {
     if(f.nickname == nickname)
     {
-      data = f.data;
-      return true;
+      if(f.hasData)
+        data = f.data;
+      return f.hasData;
     }
   }
   return false;
@@ -2595,6 +2596,7 @@ RDResult RenderDoc::ReadExternalFiles(RDCFile *rdc)
       {
         file.data = f.data;
         file.filepath.clear();
+        file.hasData = true;
         break;
       }
     }

renderdoc/core/core.h

@@ -656,11 +656,18 @@ private:
   struct TrackedFile
   {
     TrackedFile() = default;
-    TrackedFile(const rdcstr &name, const rdcstr &path) : nickname(name), filepath(path) {}
-    TrackedFile(const rdcstr &name, const bytebuf &contents) : nickname(name), data(contents) {}
+    TrackedFile(const rdcstr &name, const rdcstr &path)
+        : nickname(name), filepath(path), hasData(false)
+    {
+    }
+    TrackedFile(const rdcstr &name, const bytebuf &contents)
+        : nickname(name), data(contents), hasData(true)
+    {
+    }
     rdcstr nickname;
     rdcstr filepath;
     bytebuf data;
+    bool hasData;
   };
 
   void SyncAvailableGPUThread();