Fix the misalignment on CrOS of the tab background images

chrome/browser/ui/views/tabs/tab_strip.cc

Index: chrome/browser/ui/views/tabs/tab_strip.cc
diff --git a/chrome/browser/ui/views/tabs/tab_strip.cc b/chrome/browser/ui/views/tabs/tab_strip.cc
index e0356c8cc2fc3cf955c40c86c119c24503db4a4c..a20757e5750900a16fefb25e0df63af5413b161e 100644
--- a/chrome/browser/ui/views/tabs/tab_strip.cc
+++ b/chrome/browser/ui/views/tabs/tab_strip.cc
@@ -25,6 +25,7 @@
 #include "chrome/browser/ui/views/tabs/tab_drag_controller.h"
 #include "chrome/browser/ui/views/tabs/tab_strip_controller.h"
 #include "chrome/browser/ui/views/tabs/tab_strip_observer.h"
+#include "chrome/browser/ui/views/tabs/tab_util.h"
 #include "chrome/browser/ui/views/touch_uma/touch_uma.h"
 #include "content/public/browser/user_metrics.h"
 #include "grit/generated_resources.h"
@@ -413,16 +414,21 @@ gfx::ImageSkia NewTabButton::GetBackgroundImage(
     views::CustomButton::ButtonState state,
     ui::ScaleFactor scale_factor) const {
   int background_id = 0;
+  int background_overlay_id = 0;
   if (ShouldUseNativeFrame()) {
     background_id = IDR_THEME_TAB_BACKGROUND_V;
+    background_overlay_id = IDR_THEME_TAB_BACKGROUND_V_OVERLAY;
   } else if (tab_strip_->controller()->IsIncognito()) {
     background_id = IDR_THEME_TAB_BACKGROUND_INCOGNITO;
+    background_overlay_id = IDR_THEME_TAB_BACKGROUND_INCOGNITO_OVERLAY;
 #if defined(OS_WIN)
   } else if (win8::IsSingleWindowMetroMode()) {
     background_id = IDR_THEME_TAB_BACKGROUND_V;
+    background_overlay_id = IDR_THEME_TAB_BACKGROUND_V_OVERLAY;
 #endif
   } else {
     background_id = IDR_THEME_TAB_BACKGROUND;
+    background_overlay_id = IDR_THEME_TAB_BACKGROUND_OVERLAY;
   }
 
   int alpha = 0;
@@ -443,6 +449,9 @@ gfx::ImageSkia NewTabButton::GetBackgroundImage(
       GetThemeProvider()->GetImageSkiaNamed(IDR_NEWTAB_BUTTON_MASK);
   int height = mask->height();
   int width = mask->width();
+  // This method assumes that the button is |width|x|height|.
+  DCHECK_EQ(width, NewTabButton::width());
+  DCHECK_EQ(height, NewTabButton::height());
 
   // The canvas and mask has to use the same scale factor.
   if (!mask->HasRepresentation(scale_factor))
@@ -450,25 +459,21 @@ gfx::ImageSkia NewTabButton::GetBackgroundImage(
 
   gfx::Canvas canvas(gfx::Size(width, height), scale_factor, false);
 
-  // For custom images the background starts at the top of the tab strip.
-  // Otherwise the background starts at the top of the frame.
-  gfx::ImageSkia* background =
-      GetThemeProvider()->GetImageSkiaNamed(background_id);
-  int offset_y = GetThemeProvider()->HasCustomImage(background_id) ?
-      0 : background_offset_.y();
 
-  // The new tab background is mirrored in RTL mode, but the theme background
-  // should never be mirrored. Mirror it here to compensate.
-  float x_scale = 1.0f;
-  int x = GetMirroredX() + background_offset_.x();
+  // The new tab button is mirrored in RTL mode, but the button's background
+  // should never be mirrored.
   if (base::i18n::IsRTL()) {
-    x_scale = -1.0f;
-    // Offset by |width| such that the same region is painted as if there was no
-    // flip.
-    x += width;
+    // Translate by |width| such that the same region is painted as if there was
+    // no flip.
+    canvas.Translate(gfx::Vector2d(width, 0));
+    canvas.Scale(-1, 1);
   }
-  canvas.TileImageInt(*background, x, newtab_button_v_offset() + offset_y,
-                      x_scale, 1.0f, 0, 0, width, height);
+
+  int x = GetMirroredX() + background_offset_.x();
+  gfx::ImageSkia tiled_background = TabUtil::CreateTiledInactiveBackground(
+      GetThemeProvider(), background_id, background_overlay_id,
+      background_offset_.y(), x, newtab_button_v_offset(), width, height);
+  canvas.DrawImageInt(tiled_background, 0, 0);
 
   if (alpha != 255) {
     SkPaint paint;