IJPL-157156 Make the editor tabs at least as high as tool window headers

Not clear what caused this regression, but there's an easy way to both
fix it and prevent it. We just need to make sure that the editor tabs
are always at least as high as tool window headers.

The only trick is that the height is calculated in JBTabsImpl, which
is used not just for the editor tabs. So we add an internal protected
method here and override it in the editor tabs only.

GitOrigin-RevId: 106860cf0eb9ff8f0acd3c2121a061b16e0fb301

platform/platform-api/src/com/intellij/ui/tabs/impl/JBTabsImpl.kt

@@ -2167,13 +2167,24 @@ open class JBTabsImpl internal constructor(
   private fun computeHeaderFitSize(): Dimension {
     val max = computeMaxSize()
     if (tabsPosition == JBTabsPosition.top || tabsPosition == JBTabsPosition.bottom) {
-      return Dimension(size.width, if (horizontalSide) max(max.label.height, max.toolbar.height) else max.label.height)
+      return Dimension(
+        size.width,
+        if (horizontalSide) {
+          max(max.label.height, max.toolbar.height).coerceAtLeast(minHeaderHeight())
+        }
+        else {
+          max.label.height
+        }
+      )
     }
     else {
       return Dimension(max.label.width + if (horizontalSide) 0 else max.toolbar.width, size.height)
     }
   }
 
+  @Internal
+  protected open fun minHeaderHeight(): Int = 0
+
   fun layoutComp(componentX: Int, componentY: Int, component: JComponent, deltaWidth: Int, deltaHeight: Int): Rectangle {
     return layoutComp(
       bounds = Rectangle(componentX, componentY, width, height),

platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/EditorTabbedContainer.kt

@@ -64,6 +64,7 @@ import com.intellij.util.ui.TimedDeadzone
 import com.intellij.util.ui.UIUtil
 import kotlinx.coroutines.*
 import org.jetbrains.annotations.ApiStatus
+import org.jetbrains.annotations.ApiStatus.Internal
 import java.awt.*
 import java.awt.datatransfer.DataFlavor
 import java.awt.datatransfer.Transferable
@@ -592,6 +593,9 @@ private class EditorTabs(
 
   override fun getEditorWindow(): EditorWindow = window
 
+  @Internal
+  override fun minHeaderHeight(): Int = JBUI.CurrentTheme.ToolWindow.headerHeight()
+
   override fun createRowLayout(): TabLayout {
     if (!isSingleRow || (isHorizontalTabs && (TabLayout.showPinnedTabsSeparately() || !UISettings.getInstance().hideTabsIfNeeded))) {
       return when {