Send array of paint rects and bitmaps as opposed to a Union

chrome/browser/renderer_host/backing_store_mac.cc

 // Copyright (c) 2006-2008 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.
 
 #include "chrome/browser/renderer_host/backing_store.h"
 
 #include "base/logging.h"
 #include "chrome/common/transport_dib.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 BackingStore::BackingStore(const gfx::Size& size)
     : size_(size) {
   if (!canvas_.initialize(size.width(), size.height(), true))
     SK_CRASH();
 }
 
 BackingStore::~BackingStore() {
 }
 
 void BackingStore::PaintRect(base::ProcessHandle process,
                              TransportDIB* bitmap,
-                             const gfx::Rect& bitmap_rect) {
+                             const gfx::Rect& bitmap_rect,
+                             const gfx::Rect& paint_rect) {
+  DCHECK(bitmap_rect.Contains(paint_rect) &&
+         paint_rect.x() < kMaxBitmapLengthAllowed &&
+         paint_rect.y() < kMaxBitmapLengthAllowed);
   SkBitmap skbitmap;
   skbitmap.setConfig(SkBitmap::kARGB_8888_Config, bitmap_rect.width(),
                      bitmap_rect.height(), 4 * bitmap_rect.width());
 
   skbitmap.setPixels(bitmap->memory());
-
-  canvas_.drawBitmap(skbitmap, bitmap_rect.x(), bitmap_rect.y());
+  SkIRect src_rect;
+  src_rect.set(paint_rect.x(), paint_rect.y(),
+               paint_rect.right(), paint_rect.bottom());
+  src_rect.offset(-bitmap_rect.x(), -bitmap_rect.y());
+  SkRect dst_rect;
+  dst_rect.iset(paint_rect.x(), paint_rect.y(),
+                paint_rect.right(), paint_rect.bottom());
+  canvas_.drawBitmapRect(skbitmap, &src_rect, dst_rect);
 }
 
 void BackingStore::ScrollRect(base::ProcessHandle process,
                               TransportDIB* bitmap,
                               const gfx::Rect& bitmap_rect,
                               int dx, int dy,
                               const gfx::Rect& clip_rect,
                               const gfx::Size& view_size) {
   // WARNING: this is temporary code until a real solution is found for Mac and
   // Linux.
@@ skipping 68 matching lines @@
       x += (clip_rect.bottom() - 1) * stride;
 
       for (int i = clip_rect.y(); i < clip_rect.height() + dy; ++i) {
         memcpy(x, x + stride * dy, len);
         x -= stride;
       }
     }
   }
 
   // Now paint the new bitmap data.
-  PaintRect(process, bitmap, bitmap_rect);
+  PaintRect(process, bitmap, bitmap_rect, bitmap_rect);
   return;
 }