Fix the misalignment on CrOS of the tab background images

chrome/browser/ui/cocoa/tabs/tab_view.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_view.h"
 
 #include "base/logging.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "chrome/browser/themes/theme_service.h"
 #import "chrome/browser/ui/cocoa/nsview_additions.h"
@@ skipping 284 matching lines @@
 
   // Themes don't have an inactive image so only look for one if there's no
   // theme.
   bool active = [[self window] isKeyWindow] || [[self window] isMainWindow] ||
                 !themeProvider->UsingDefaultTheme();
   return themeProvider->GetNSImageColorNamed(bitmapResources[active][selected]);
 }
 
 // Draws the active tab background.
 - (void)drawFillForActiveTab:(NSRect)dirtyRect {
+  gfx::ScopedNSGraphicsContextSaveGState scopedGState;
+  NSGraphicsContext* context = [NSGraphicsContext currentContext];
+  NSPoint position = [[self window]
+      themeImagePositionForAlignment: THEME_IMAGE_ALIGN_WITH_TAB_STRIP];

[sail, 2013/08/22 18:23:01]

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+  [context cr_setPatternPhase:position forView:self];
+
   NSColor* backgroundImageColor = [self backgroundColorForSelected:YES];
   [backgroundImageColor set];
 
   // Themes can have partially transparent images. NSRectFill() is measurably
   // faster though, so call it for the known-safe default theme.
   ThemeService* themeProvider =
       static_cast<ThemeService*>([[self window] themeProvider]);
   if (themeProvider && themeProvider->UsingDefaultTheme())
     NSRectFill(dirtyRect);
   else
     NSRectFillUsingOperation(dirtyRect, NSCompositeSourceOver);
 }
 
 // Draws the tab background.
 - (void)drawFill:(NSRect)dirtyRect {
   gfx::ScopedNSGraphicsContextSaveGState scopedGState;
   NSGraphicsContext* context = [NSGraphicsContext currentContext];
   CGContextRef cgContext = static_cast<CGContextRef>([context graphicsPort]);
 
   ThemeService* themeProvider =
       static_cast<ThemeService*>([[self window] themeProvider]);
-  NSPoint position = [[self window]
-      themeImagePositionForAlignment: THEME_IMAGE_ALIGN_WITH_TAB_STRIP];
-  [context cr_setPatternPhase:position forView:self];
 
   CGImageRef mask([self tabClippingMask]);
   CGRect maskBounds = CGRectMake(0, 0, maskCacheWidth_, kMaskHeight);
   CGContextClipToMask(cgContext, maskBounds, mask);
 
   bool selected = [self state];
   if (selected) {
     [self drawFillForActiveTab:dirtyRect];
     return;
   }
 
   // Background tabs should not paint over the tab strip separator, which is
   // two pixels high in both lodpi and hidpi.
   if (dirtyRect.origin.y < 1)
     dirtyRect.origin.y = 2 * [self cr_lineWidth];
 
-  // Draw the tab background.
+  // Draw the tinted frame image.
+  NSPoint position = [[self window]
+      themeImagePositionForAlignment: THEME_IMAGE_ALIGN_WITH_FRAME];

[sail, 2013/08/22 18:23:01]

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+  [context cr_setPatternPhase:position forView:self];
   NSColor* backgroundImageColor = [self backgroundColorForSelected:NO];
   [backgroundImageColor set];
 
   // Themes can have partially transparent images. NSRectFill() is measurably
   // faster though, so call it for the known-safe default theme.
   bool usingDefaultTheme = themeProvider && themeProvider->UsingDefaultTheme();
   if (usingDefaultTheme)
     NSRectFill(dirtyRect);
   else
     NSRectFillUsingOperation(dirtyRect, NSCompositeSourceOver);
 
+  // If the theme is not the default theme, it may provide a custom overlay
+  // image. The overlay image is aligned with the top of the tab.
+  NSColor* overlayImageColor = nil;
+  if (themeProvider &&
+      themeProvider->HasCustomImage(IDR_THEME_TAB_BACKGROUND_OVERLAY)) {
+    overlayImageColor = themeProvider->GetNSImageColorNamed(
+        IDR_THEME_TAB_BACKGROUND_OVERLAY);
+  }
+  if (overlayImageColor) {
+    position = [[self window]
+        themeImagePositionForAlignment: THEME_IMAGE_ALIGN_WITH_TAB_STRIP];

[sail, 2013/08/22 18:23:01]

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+    [context cr_setPatternPhase:position forView:self];
+    [overlayImageColor set];
+    NSRectFillUsingOperation(dirtyRect, NSCompositeSourceOver);
+  }
+
   // Draw the glow for hover and the overlay for alerts.
   CGFloat hoverAlpha = [self hoverAlpha];
   CGFloat alertAlpha = [self alertAlpha];
   if (hoverAlpha > 0 || alertAlpha > 0) {
     gfx::ScopedNSGraphicsContextSaveGState contextSave;
     CGContextBeginTransparencyLayer(cgContext, 0);
 
     // The alert glow overlay is like the selected state but at most at most 80%
     // opaque. The hover glow brings up the overlay's opacity at most 50%.
     CGFloat backgroundAlpha = 0.8 * alertAlpha;
     backgroundAlpha += (1 - backgroundAlpha) * 0.5 * hoverAlpha;
     CGContextSetAlpha(cgContext, backgroundAlpha);
 
     [self drawFillForActiveTab:dirtyRect];
 
     // ui::ThemeProvider::HasCustomImage is true only if the theme provides the
     // image. However, even if the theme doesn't provide a tab background, the
     // theme machinery will make one if given a frame image. See
     // BrowserThemePack::GenerateTabBackgroundImages for details.
     BOOL hasCustomTheme = themeProvider &&
-        (themeProvider->HasCustomImage(IDR_THEME_TAB_BACKGROUND) ||
+        (themeProvider->HasCustomImage(IDR_THEME_TAB_BACKGROUND_OVERLAY) ||
          themeProvider->HasCustomImage(IDR_THEME_FRAME));
     // Draw a mouse hover gradient for the default themes.
     if (hoverAlpha > 0) {
       if (themeProvider && !hasCustomTheme) {
         base::scoped_nsobject<NSGradient> glow([NSGradient alloc]);
         [glow initWithStartingColor:[NSColor colorWithCalibratedWhite:1.0
                                         alpha:1.0 * hoverAlpha]
                         endingColor:[NSColor colorWithCalibratedWhite:1.0
                                                                 alpha:0.0]];
         NSRect rect = [self bounds];
@@ skipping 317 matching lines @@
   CGFloat middleWidth = tabWidth - leftWidth - rightWidth;
   NSRect middleRect = NSMakeRect(leftWidth, 0, middleWidth, kFillHeight);
   [[NSColor whiteColor] setFill];
   NSRectFill(middleRect);
 
   maskCache_.reset(CGBitmapContextCreateImage(maskContext));
   return maskCache_;
 }
 
 @end  // @implementation TabView(Private)