DevTools: Show screenshots on the main flamechart

third_party/WebKit/Source/devtools/front_end/perf_ui/FlameChart.js

Index: third_party/WebKit/Source/devtools/front_end/perf_ui/FlameChart.js
diff --git a/third_party/WebKit/Source/devtools/front_end/perf_ui/FlameChart.js b/third_party/WebKit/Source/devtools/front_end/perf_ui/FlameChart.js
index 3cc65acc1bbcb7cc1d11fa1ae1ab84f0061bf4d9..87e30466edbe6aff37f138dacf6f5ec12d99d69a 100644
--- a/third_party/WebKit/Source/devtools/front_end/perf_ui/FlameChart.js
+++ b/third_party/WebKit/Source/devtools/front_end/perf_ui/FlameChart.js
@@ -1153,8 +1153,11 @@ PerfUI.FlameChart = class extends PerfUI.ChartViewport {
     if (!isLastGroup && groups[index + 1].style.nestingLevel > style.nestingLevel)
       return true;
     var nextGroupLevel = isLastGroup ? this._dataProvider.maxStackDepth() : groups[index + 1].startLevel;
-    // For groups that only have one line and share header line, pretend these are not collapsible.
-    return nextGroupLevel !== groups[index].startLevel + 1;
+    if (nextGroupLevel !== groups[index].startLevel + 1)
+      return true;
+    // For groups that only have one line and share header line, pretend these are not collapsible
+    // unless the itemsHeight does not match the headerHeight
+    return style.height !== style.itemsHeight;
   }
 
   /**