[Aura] Fix software compositing blits to WS_EX_LAYERED windows.

content/browser/renderer_host/software_output_device_win.cc

Index: content/browser/renderer_host/software_output_device_win.cc
diff --git a/content/browser/renderer_host/software_output_device_win.cc b/content/browser/renderer_host/software_output_device_win.cc
index 29c4542bbc6feabc9a86bc4274c8f8463e1f1f17..c3af6a24cce3451a224a130f87ca7019e0743272 100644
--- a/content/browser/renderer_host/software_output_device_win.cc
+++ b/content/browser/renderer_host/software_output_device_win.cc
@@ -8,16 +8,20 @@
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "ui/compositor/compositor.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/canvas_skia_paint.h"
 #include "ui/gfx/gdi_util.h"
 
 namespace content {
 
 SoftwareOutputDeviceWin::SoftwareOutputDeviceWin(ui::Compositor* compositor)
-    : compositor_(compositor) {
+    : hwnd_(compositor->widget()),
+      is_hwnd_composited_(false) {
   // TODO(skaslev) Remove this when crbug.com/180702 is fixed.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  hwnd_ = compositor->widget();
+  LONG style = GetWindowLong(hwnd_, GWL_EXSTYLE);
+  is_hwnd_composited_ = !!(style & WS_EX_COMPOSITED);
 }
 
 SoftwareOutputDeviceWin::~SoftwareOutputDeviceWin() {
@@ -27,18 +31,30 @@ SoftwareOutputDeviceWin::~SoftwareOutputDeviceWin() {
 void SoftwareOutputDeviceWin::Resize(gfx::Size viewport_size) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  cc::SoftwareOutputDevice::Resize(viewport_size);
+  if (viewport_size_ == viewport_size)
+    return;
+
+  viewport_size_ = viewport_size;
+  contents_.reset(new gfx::Canvas(viewport_size, ui::SCALE_FACTOR_100P, false));
   memset(&bitmap_info_, 0, sizeof(bitmap_info_));
   gfx::CreateBitmapHeader(viewport_size_.width(), viewport_size_.height(),
                           &bitmap_info_.bmiHeader);
 }
 
+SkCanvas* SoftwareOutputDeviceWin::BeginPaint(gfx::Rect damage_rect) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(contents_);
+
+  damage_rect_ = damage_rect;
+  return contents_ ? contents_->sk_canvas() : NULL;
+}
+
 void SoftwareOutputDeviceWin::EndPaint(cc::SoftwareFrameData* frame_data) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK(device_);
+  DCHECK(contents_);
   DCHECK(frame_data == NULL);
 
-  if (!device_)
+  if (!contents_)
     return;
 
   gfx::Rect rect = damage_rect_;
@@ -46,16 +62,38 @@ void SoftwareOutputDeviceWin::EndPaint(cc::SoftwareFrameData* frame_data) {
   if (rect.IsEmpty())
     return;
 
-  const SkBitmap& bitmap = device_->accessBitmap(false);
-  HDC hdc = ::GetDC(hwnd_);
-  gfx::StretchDIBits(hdc,
-                     rect.x(), rect.y(),
-                     rect.width(), rect.height(),
-                     rect.x(), rect.y(),
-                     rect.width(), rect.height(),
-                     bitmap.getPixels(),
-                     &bitmap_info_);
-  ::ReleaseDC(hwnd_, hdc);
+  SkCanvas* canvas = contents_->sk_canvas();
+  DCHECK(canvas);
+  if (is_hwnd_composited_) {
+    RECT wr;
+    GetWindowRect(hwnd_, &wr);
+    SIZE size = {wr.right - wr.left, wr.bottom - wr.top};
+    POINT position = {wr.left, wr.top};
+    POINT zero = {0, 0};
+    BLENDFUNCTION blend = {AC_SRC_OVER, 0x00, 0xFF, AC_SRC_ALPHA};
+
+    DWORD style = GetWindowLong(hwnd_, GWL_EXSTYLE);
+    style &= ~WS_EX_COMPOSITED;
+    style |= WS_EX_LAYERED;
+    SetWindowLong(hwnd_, GWL_EXSTYLE, style);
+
+    HDC dib_dc = skia::BeginPlatformPaint(canvas);
+    ::UpdateLayeredWindow(hwnd_, NULL, &position, &size, dib_dc, &zero,
+                          RGB(0xFF, 0xFF, 0xFF), &blend, ULW_ALPHA);
+    skia::EndPlatformPaint(canvas);
+  } else {
+    SkDevice* device = canvas->getDevice();
+    const SkBitmap& bitmap = device->accessBitmap(false);
+    HDC hdc = ::GetDC(hwnd_);
+    gfx::StretchDIBits(hdc,
+                       rect.x(), rect.y(),
+                       rect.width(), rect.height(),
+                       rect.x(), rect.y(),
+                       rect.width(), rect.height(),
+                       bitmap.getPixels(),
+                       &bitmap_info_);
+    ::ReleaseDC(hwnd_, hdc);
+  }
 }
 
 }  // namespace content