Attempt 2 at:

chrome/browser/views/tabs/tab.cc

Index: chrome/browser/views/tabs/tab.cc
diff --git a/chrome/browser/views/tabs/tab.cc b/chrome/browser/views/tabs/tab.cc
index ec34e42d1792f9e58d751842e4b1383a71bb843c..75de074ac84214790ec5de892d32f6a184ecbefc 100644
--- a/chrome/browser/views/tabs/tab.cc
+++ b/chrome/browser/views/tabs/tab.cc
@@ -23,6 +23,7 @@
 #include "grit/theme_resources.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "views/controls/button/image_button.h"
+#include "views/widget/root_view.h"
 #include "views/widget/tooltip_manager.h"
 #include "views/widget/widget.h"
 #include "views/window/non_client_view.h"
@@ -105,7 +106,7 @@ const char Tab::kViewClassName[] = "browser/tabs/Tab";
 // Tab, public:
 
 Tab::Tab(TabController* controller)
-    : BaseTab(controller),
+    : BaseTab(controller, true),
       showing_icon_(false),
       showing_close_button_(false),
       close_button_color_(NULL),
@@ -232,13 +233,7 @@ void Tab::Paint(gfx::Canvas* canvas) {
     PaintIcon(canvas);
 
   // If the close button color has changed, generate a new one.
-  if (!close_button_color_ || title_color != close_button_color_) {
-    close_button_color_ = title_color;
-    ResourceBundle& rb = ResourceBundle::GetSharedInstance();
-    close_button()->SetBackground(close_button_color_,
-        rb.GetBitmapNamed(IDR_TAB_CLOSE),
-        rb.GetBitmapNamed(IDR_TAB_CLOSE_MASK));
-  }
+  SetCloseButtonColor(title_color);
 }
 
 void Tab::Layout() {
@@ -286,6 +281,7 @@ void Tab::Layout() {
 
   // Size the Close button.
   showing_close_button_ = ShouldShowCloseBox();
+  gfx::Insets near_insets;
   if (showing_close_button_) {
     int close_button_top =
         kTopPadding + kCloseButtonVertFuzz +
@@ -295,10 +291,24 @@ void Tab::Layout() {
                               close_button_top, close_button_width(),
                               close_button_height());
     close_button()->SetVisible(true);
+    int avail_width = width() - close_button()->bounds().right();
+    if (avail_width > 0) {
+      View* root = GetRootView();
+      if (root) {  // Root is NULL when dragging.
+        // Enable mouse near events for the region from the top of the browser
+        // to the bottom of the tab.
+        gfx::Point loc;
+        ConvertPointToView(close_button(), GetRootView(), &loc);
+        near_insets.Set(loc.y(), close_button()->x(),
+                        height() - close_button()->bounds().bottom(),
+                        avail_width);
+      }
+    }
   } else {
     close_button()->SetBounds(0, 0, 0, 0);
     close_button()->SetVisible(false);
   }
+  close_button()->RegisterForMouseNearEvents(near_insets);
 
   int title_left = favicon_bounds_.right() + kFavIconTitleSpacing;
   int title_top = kTopPadding + (content_height - font_height()) / 2;