[XProf: trace viewer] Pre-calculate visible level offsets in Timeline.

frontend/app/components/trace_viewer_v2/application.cc

@@ -7,6 +7,7 @@
 #include <stdlib.h>
 
 #include <memory>
+#include <tuple>
 
 #include "absl/time/clock.h"
 #include "absl/time/time.h"
@@ -27,6 +28,15 @@ const char* const kWindowTarget = EMSCRIPTEN_EVENT_TARGET_WINDOW;
 const char* const kCanvasTarget = "#canvas";
 constexpr float kScrollbarSize = 10.0f;
 
+void ApplyDefaultTraceViewerStyles() {
+  ImGuiStyle& style = ImGui::GetStyle();
+  style.ScrollbarSize = kScrollbarSize;
+  style.WindowRounding = 0.0f;
+  style.WindowPadding = ImVec2(0.0f, 0.0f);
+  style.CellPadding = ImVec2(0.0f, 0.0f);
+  style.ItemSpacing = ImVec2(0.0f, 0.0f);
+}
+
 void ApplyLightTheme() {
   ImGui::StyleColorsLight();
   ImGuiStyle& style = ImGui::GetStyle();
@@ -57,7 +67,7 @@ void Application::Initialize() {
   fonts::LoadFonts(initial_canvas_state.device_pixel_ratio());
   // TODO: b/450584482 - Add a dark theme for the timeline.
   ApplyLightTheme();
-  ImGui::GetStyle().ScrollbarSize = kScrollbarSize;
+  ApplyDefaultTraceViewerStyles();
 
   // Initialize the platform
   platform_ = std::make_unique<WGPURenderPlatform>();

frontend/app/components/trace_viewer_v2/color/colors.h

@@ -24,14 +24,6 @@ inline constexpr ImU32 kPurple70 = 0xFFFF97C5;
 inline constexpr ImU32 kYellow90 = 0xFF7CE0FF;
 // go/keep-sorted end
 
-// Baseline palette:
-// go/keep-sorted start
-// Baseline Primary: #0B57D0
-inline constexpr ImU32 kPrimary40 = 0xFFD0570B;
-// Baseline Secondary: #C2E7FF
-inline constexpr ImU32 kSecondary90 = 0xFFFFE7C2;
-// go/keep-sorted end
-
 }  // namespace traceviewer
 
 #endif  // THIRD_PARTY_XPROF_FRONTEND_APP_COMPONENTS_TRACE_VIEWER_V2_COLOR_COLORS_H_

frontend/app/components/trace_viewer_v2/timeline/BUILD

@@ -44,7 +44,6 @@ cc_library(
     ],
     deps = [
         ":constants",
-        ":draw_utils",
         ":time_range",
         "//third_party/dear_imgui",
         "@com_google_absl//absl/base:nullability",
@@ -94,18 +93,6 @@ cc_library(
     ],
 )
 
-cc_library(
-    name = "draw_utils",
-    srcs = ["draw_utils.cc"],
-    hdrs = ["draw_utils.h"],
-    deps = [
-        ":constants",
-        "//third_party/dear_imgui",
-        "@com_google_absl//absl/strings:string_view",
-        "@org_xprof//frontend/app/components/trace_viewer_v2/color:colors",
-    ],
-)
-
 cc_test(
     name = "data_provider_test",
     srcs = ["data_provider_test.cc"],

frontend/app/components/trace_viewer_v2/timeline/data_provider.cc

@@ -303,7 +303,7 @@ void DataProvider::ProcessTraceEvents(const ParsedTraceEvents& parsed_events,
                                       Timeline& timeline) {
   if (parsed_events.flame_events.empty() &&
       parsed_events.counter_events.empty()) {
-    timeline.set_timeline_data({});
+    timeline.SetTimelineData({});
     timeline.set_data_time_range(TimeRange::Zero());
     timeline.SetVisibleRange(TimeRange::Zero());
     return;
@@ -372,7 +372,7 @@ void DataProvider::ProcessTraceEvents(const ParsedTraceEvents& parsed_events,
     }
   }
 
-  timeline.set_timeline_data(CreateTimelineData(trace_info, time_bounds));
+  timeline.SetTimelineData(CreateTimelineData(trace_info, time_bounds));
 
   // Don't need to check for max_time because the TimeRange constructor will
   // handle any potential issues with max_time.