Remove NativeThemeWin::PaintIndirect

ui/native_theme/native_theme_win.cc

Index: ui/native_theme/native_theme_win.cc
diff --git a/ui/native_theme/native_theme_win.cc b/ui/native_theme/native_theme_win.cc
index 69954dd8d2bedcede4e6fb5a7c83566b33f0be09..91c1061a7ede156199cbf114d44c77a3d5653a61 100644
--- a/ui/native_theme/native_theme_win.cc
+++ b/ui/native_theme/native_theme_win.cc
@@ -255,39 +255,7 @@ void NativeThemeWin::Paint(SkCanvas* canvas,
       break;
   }
 
-  bool needs_paint_indirect = false;
-  if (!skia::SupportsPlatformPaint(canvas)) {
-    // This block will only get hit with --enable-accelerated-drawing flag.
-    needs_paint_indirect = true;
-  } else {
-    // Scrollbar components on Windows Classic theme (on all Windows versions)
-    // have particularly problematic alpha values, so always draw them
-    // indirectly. In addition, scrollbar thumbs and grippers for the Windows XP
-    // theme (available only on Windows XP) also need their alpha values
-    // fixed.
-    switch (part) {
-      case kScrollbarDownArrow:
-      case kScrollbarUpArrow:
-      case kScrollbarLeftArrow:
-      case kScrollbarRightArrow:
-        needs_paint_indirect = !GetThemeHandle(SCROLLBAR);
-        break;
-      case kScrollbarHorizontalThumb:
-      case kScrollbarVerticalThumb:
-      case kScrollbarHorizontalGripper:
-      case kScrollbarVerticalGripper:
-        needs_paint_indirect = !GetThemeHandle(SCROLLBAR) ||
-            base::win::GetVersion() == base::win::VERSION_XP;
-        break;
-      default:
-        break;
-    }
-  }
-
-  if (needs_paint_indirect)
-    PaintIndirect(canvas, part, state, rect, extra);
-  else
-    PaintDirect(canvas, part, state, rect, extra);
+  PaintDirect(canvas, part, state, rect, extra);

[Peter Kasting, 2016/06/29 23:20:01]

This is now the only caller of this function.  I would combine the two into one
function.

This should allow eliminating all the handling code in that function for the
four cases covered in the switch above, I believe.

 }
 
 NativeThemeWin::NativeThemeWin()
@@ -672,76 +640,6 @@ SkColor NativeThemeWin::GetSystemColor(ColorId color_id) const {
   return GetAuraColor(color_id, this);
 }
 
-void NativeThemeWin::PaintIndirect(SkCanvas* canvas,
-                                   Part part,
-                                   State state,
-                                   const gfx::Rect& rect,
-                                   const ExtraParams& extra) const {
-  // TODO(asvitkine): This path is pretty inefficient - for each paint operation
-  //                  it creates a new offscreen bitmap Skia canvas. This can
-  //                  be sped up by doing it only once per part/state and
-  //                  keeping a cache of the resulting bitmaps.
-
-  // Create an offscreen canvas that is backed by an HDC.
-  sk_sp<skia::BitmapPlatformDevice> device(
-      skia::BitmapPlatformDevice::Create(
-          rect.width(), rect.height(), false, NULL));
-  DCHECK(device);
-  SkCanvas offscreen_canvas(device.get());
-  DCHECK(skia::SupportsPlatformPaint(&offscreen_canvas));
-
-  // Some of the Windows theme drawing operations do not write correct alpha
-  // values for fully-opaque pixels; instead the pixels get alpha 0. This is
-  // especially a problem on Windows XP or when using the Classic theme.
-  //
-  // To work-around this, mark all pixels with a placeholder value, to detect
-  // which pixels get touched by the paint operation. After paint, set any
-  // pixels that have alpha 0 to opaque and placeholders to fully-transparent.
-  const SkColor placeholder = SkColorSetARGB(1, 0, 0, 0);
-  offscreen_canvas.clear(placeholder);
-
-  // Offset destination rects to have origin (0,0).
-  gfx::Rect adjusted_rect(rect.size());
-  ExtraParams adjusted_extra(extra);
-  switch (part) {
-    case kProgressBar:
-      adjusted_extra.progress_bar.value_rect_x = 0;
-      adjusted_extra.progress_bar.value_rect_y = 0;
-      break;
-    case kScrollbarHorizontalTrack:
-    case kScrollbarVerticalTrack:
-      adjusted_extra.scrollbar_track.track_x = 0;
-      adjusted_extra.scrollbar_track.track_y = 0;
-      break;
-    default:
-      break;
-  }
-  // Draw the theme controls using existing HDC-drawing code.
-  PaintDirect(&offscreen_canvas, part, state, adjusted_rect, adjusted_extra);
-
-  SkBitmap bitmap = skia::ReadPixels(&offscreen_canvas);
-
-  // Post-process the pixels to fix up the alpha values (see big comment above).
-  const SkPMColor placeholder_value = SkPreMultiplyColor(placeholder);
-  const int pixel_count = rect.width() * rect.height();
-  SkPMColor* pixels = bitmap.getAddr32(0, 0);
-  for (int i = 0; i < pixel_count; i++) {
-    if (pixels[i] == placeholder_value) {
-      // Pixel wasn't touched - make it fully transparent.
-      pixels[i] = SkPackARGB32(0, 0, 0, 0);
-    } else if (SkGetPackedA32(pixels[i]) == 0) {
-      // Pixel was touched but has incorrect alpha of 0, make it fully opaque.
-      pixels[i] = SkPackARGB32(0xFF,
-                               SkGetPackedR32(pixels[i]),
-                               SkGetPackedG32(pixels[i]),
-                               SkGetPackedB32(pixels[i]));
-    }
-  }
-
-  // Draw the offscreen bitmap to the destination canvas.
-  canvas->drawBitmap(bitmap, rect.x(), rect.y());
-}
-
 HRESULT NativeThemeWin::GetThemePartSize(ThemeName theme_name,
                                          HDC hdc,
                                          int part_id,