Distill the concept of the "tab top exclusion region", an area inside the tab

chrome/browser/ui/views/layout_constants.cc

Index: chrome/browser/ui/views/layout_constants.cc
diff --git a/chrome/browser/ui/views/layout_constants.cc b/chrome/browser/ui/views/layout_constants.cc
index 63924773fd82972277cc2cf58fee769db999b0cf..de59375c435eb208a224304b4f9e33a0ec334717 100644
--- a/chrome/browser/ui/views/layout_constants.cc
+++ b/chrome/browser/ui/views/layout_constants.cc
@@ -25,9 +25,11 @@ int GetLayoutConstant(LayoutConstant constant) {
   const int kTabMaximumTitleWidth[] = {175, 175, 175};
   const int kTabPinnedContentWidth[] = {25, 25, 25};
 #if defined(OS_MACOSX)
+  const int kTabTopExclusionHeight[] = {0, 0, 0};
   const int kTabstripNewTabButtonOverlap[] = {8, 8, 8};
   const int kTabstripTabOverlap[] = {19, 19, 19};
 #else
+  const int kTabTopExclusionHeight[] = {2, 2, 2};
   const int kTabstripNewTabButtonOverlap[] = {11, 11, 11};
   const int kTabstripTabOverlap[] = {26, 26, 26};
 #endif
@@ -78,6 +80,8 @@ int GetLayoutConstant(LayoutConstant constant) {
       return kTabMaximumTitleWidth[mode];
     case TAB_PINNED_CONTENT_WIDTH:
       return kTabPinnedContentWidth[mode];
+    case TAB_TOP_EXCLUSION_HEIGHT:
+      return kTabTopExclusionHeight[mode];
     case TOOLBAR_CONTENT_SHADOW_HEIGHT:
       return kToolbarContentShadowHeight[mode];
     case TOOLBAR_CONTENT_SHADOW_HEIGHT_ASH: