Do not convert from RectF to Rect by flooring.

content/browser/renderer_host/backing_store_mac.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 <Cocoa/Cocoa.h>
 
 #include "content/browser/renderer_host/backing_store_mac.h"
 
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/gfx/rect.h"
+#include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/scoped_cg_context_save_gstate_mac.h"
 #include "ui/surface/transport_dib.h"
 
 namespace content {
 
 // Mac Backing Stores:
 //
 // Since backing stores are only ever written to or drawn into windows, we keep
 // our backing store in a CGLayer that can get cached in GPU memory.  This
 // allows acclerated drawing into the layer and lets scrolling and such happen
@@ skipping 49 matching lines @@
     const base::Closure& completion_callback,
     bool* scheduled_completion_callback) {
   *scheduled_completion_callback = false;
   DCHECK_NE(static_cast<bool>(cg_layer()), static_cast<bool>(cg_bitmap()));
 
   TransportDIB* dib = process->GetTransportDIB(bitmap);
   if (!dib)
     return;
 
   gfx::Size pixel_size = size().Scale(device_scale_factor_);
-  gfx::Rect pixel_bitmap_rect = bitmap_rect.Scale(scale_factor);
+  gfx::Rect pixel_bitmap_rect =
+      gfx::ToEnclosingRect(bitmap_rect.Scale(scale_factor));
 
   size_t bitmap_byte_count =
       pixel_bitmap_rect.width() * pixel_bitmap_rect.height() * 4;
   DCHECK_GE(dib->size(), bitmap_byte_count);
 
   base::mac::ScopedCFTypeRef<CGDataProviderRef> data_provider(
       CGDataProviderCreateWithData(NULL, dib->memory(),
       bitmap_byte_count, NULL));
 
   base::mac::ScopedCFTypeRef<CGImageRef> bitmap_image(
       CGImageCreate(pixel_bitmap_rect.width(), pixel_bitmap_rect.height(),
           8, 32, 4 * pixel_bitmap_rect.width(),
           base::mac::GetSystemColorSpace(),
           kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host,
           data_provider, NULL, false, kCGRenderingIntentDefault));
 
   for (size_t i = 0; i < copy_rects.size(); i++) {
     const gfx::Rect& copy_rect = copy_rects[i];
-    gfx::Rect pixel_copy_rect = copy_rect.Scale(scale_factor);
+    gfx::Rect pixel_copy_rect =
+        gfx::ToEnclosingRect(copy_rect.Scale(scale_factor));
 
     // Only the subpixels given by copy_rect have pixels to copy.
     base::mac::ScopedCFTypeRef<CGImageRef> image(
         CGImageCreateWithImageInRect(bitmap_image, CGRectMake(
             pixel_copy_rect.x() - pixel_bitmap_rect.x(),
             pixel_copy_rect.y() - pixel_bitmap_rect.y(),
             pixel_copy_rect.width(),
             pixel_copy_rect.height())));
 
     if (!cg_layer()) {
@@ skipping 143 matching lines @@
                                                8, pixel_size.width() * 4,
                                                base::mac::GetSystemColorSpace(),
                                                kCGImageAlphaPremultipliedFirst |
                                                    kCGBitmapByteOrder32Host);
   DCHECK(context);
 
   return context;
 }
 
 }  // namespace content