[UI] Resolved issues caused by ImGui uplift.

- Fixed size of default font size
- Added logic to not load nullptr texture to prevent unexpected issues
- Commited out some trace viewer UI logic for now. It should be redesigned with tables in mind

src/xenia/gpu/trace_viewer.cc

@@ -815,10 +815,11 @@ void TraceViewer::DrawVertexFetcher(Shader* shader,
   }
   ImGui::BeginChild("#indices", ImVec2(0, 300));
   ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(10, 0));
-  int display_start, display_end;
-  ImGui::CalcListClipping(vertex_count, ImGui::GetTextLineHeight(),
-                          &display_start, &display_end);
-  ImGui::Dummy(ImVec2(0, (display_start)*ImGui::GetTextLineHeight()));
+  int display_start = 0;
+  int display_end = 0;
+  // ImGui::CalcListClipping(vertex_count, ImGui::GetTextLineHeight(),
+  //                         &display_start, &display_end);
+  // ImGui::Dummy(ImVec2(0, (display_start)*ImGui::GetTextLineHeight()));
   ImGui::Columns(column_count);
   if (display_start <= 1) {
     for (size_t el_index = 0; el_index < vertex_binding.attributes.size();
@@ -1641,11 +1642,12 @@ void TraceViewer::DrawStateUI() {
 
       ImGui::BeginChild("#vsvertices", ImVec2(0, 300));
 
-      int display_start, display_end;
-      ImGui::CalcListClipping(int(vertices.size() / 4),
-                              ImGui::GetTextLineHeight(), &display_start,
-                              &display_end);
-      ImGui::Dummy(ImVec2(0, (display_start)*ImGui::GetTextLineHeight()));
+      int display_start = 0;
+      int display_end = 0;
+      // ImGui::CalcListClipping(int(vertices.size() / 4),
+      //                         ImGui::GetTextLineHeight(), &display_start,
+      //                         &display_end);
+      // ImGui::Dummy(ImVec2(0, (display_start)*ImGui::GetTextLineHeight()));
 
       ImGui::Columns(int(el_size), "#vsvertices", true);
       for (size_t i = display_start; i < display_end; i++) {
@@ -1706,11 +1708,12 @@ void TraceViewer::DrawStateUI() {
       }
       ImGui::BeginChild("#indices", ImVec2(0, 300));
       ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0));
-      int display_start, display_end;
-      ImGui::CalcListClipping(1 + draw_info.index_count,
-                              ImGui::GetTextLineHeight(), &display_start,
-                              &display_end);
-      ImGui::Dummy(ImVec2(0, (display_start)*ImGui::GetTextLineHeight()));
+      int display_start = 0;
+      int display_end = 0;
+      // ImGui::CalcListClipping(1 + draw_info.index_count,
+      //                         ImGui::GetTextLineHeight(), &display_start,
+      //                         &display_end);
+      // ImGui::Dummy(ImVec2(0, (display_start)*ImGui::GetTextLineHeight()));
       ImGui::Columns(2, "#indices", true);
       ImGui::SetColumnOffset(1, 60);
       if (display_start <= 1) {

src/xenia/kernel/xam/xam_ui.cc

@@ -607,7 +607,14 @@ class GameAchievementsDialog final : public XamDialog {
     const auto start_drawing_pos = ImGui::GetCursorPos();
 
     ImGui::TableSetColumnIndex(0);
-    ImGui::Image(GetIcon(achievement_entry), default_image_icon_size);
+
+    const auto icon = GetIcon(achievement_entry);
+    if (icon) {
+      ImGui::Image(reinterpret_cast<ImTextureID>(GetIcon(achievement_entry)),
+                   default_image_icon_size);
+    } else {
+      ImGui::Dummy(default_image_icon_size);
+    }
     ImGui::TableNextColumn();
 
     ImGui::PushFont(imgui_drawer()->GetTitleFont());
@@ -742,8 +749,13 @@ class GamesInfoDialog final : public XamDialog {
 
     // First Column
     ImGui::TableSetColumnIndex(0);
-    ImGui::Image(title_icon.count(entry.id) ? title_icon.at(entry.id).get() : 0,
-                 default_image_icon_size);
+
+    if (title_icon.count(entry.id)) {
+      ImGui::Image(reinterpret_cast<ImTextureID>(title_icon.at(entry.id).get()),
+                   default_image_icon_size);
+    } else {
+      ImGui::Dummy(default_image_icon_size);
+    }
 
     // Second Column
     ImGui::TableNextColumn();
@@ -1525,10 +1537,12 @@ bool xeDrawProfileContent(ui::ImGuiDrawer* imgui_drawer, const uint64_t xuid,
   ImVec2 current_drawing_position = ImGui::GetCursorPos();
 
   // In the future it can be replaced with profile icon.
-  ImGui::Image(user_index < XUserMaxUserCount
-                   ? imgui_drawer->GetNotificationIcon(user_index)
-                   : nullptr,
-               ImVec2(default_image_size, default_image_size));
+  const auto icon = imgui_drawer->GetNotificationIcon(user_index);
+  if (icon && user_index < XUserMaxUserCount) {
+    ImGui::Image(reinterpret_cast<ImTextureID>(icon), default_image_icon_size);
+  } else {
+    ImGui::Dummy(default_image_icon_size);
+  }
 
   ImGui::SameLine();
   current_drawing_position = ImGui::GetCursorPos();