Do not convert from RectF to Rect by flooring.

content/browser/renderer_host/backing_store_aura.cc

Index: content/browser/renderer_host/backing_store_aura.cc
diff --git a/content/browser/renderer_host/backing_store_aura.cc b/content/browser/renderer_host/backing_store_aura.cc
index 73d9dad0fe9af2789d5f64e7c7b0be7e303c1ac0..2cef5a59238a8819d351211adcedc71e358cc9be 100644
--- a/content/browser/renderer_host/backing_store_aura.cc
+++ b/content/browser/renderer_host/backing_store_aura.cc
@@ -87,7 +87,7 @@ void BackingStoreAura::PaintToBackingStore(
   if (bitmap_rect.IsEmpty())
     return;
 
-  gfx::Rect pixel_bitmap_rect = bitmap_rect.Scale(scale_factor);
+  gfx::Rect pixel_bitmap_rect = bitmap_rect.ScaleUnsafe(scale_factor);
 
   const int width = pixel_bitmap_rect.width();
   const int height = pixel_bitmap_rect.height();
@@ -107,7 +107,7 @@ void BackingStoreAura::PaintToBackingStore(
   sk_bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
   sk_bitmap.setPixels(dib->memory());
   for (size_t i = 0; i < copy_rects.size(); i++) {
-    const gfx::Rect pixel_copy_rect = copy_rects[i].Scale(scale_factor);
+    const gfx::Rect pixel_copy_rect = copy_rects[i].ScaleUnsafe(scale_factor);
     int x = pixel_copy_rect.x() - pixel_bitmap_rect.x();
     int y = pixel_copy_rect.y() - pixel_bitmap_rect.y();
     SkIRect srcrect = SkIRect::MakeXYWH(x, y,
@@ -115,7 +115,7 @@ void BackingStoreAura::PaintToBackingStore(
         pixel_copy_rect.height());
 
     const gfx::Rect pixel_copy_dst_rect =
-        copy_rects[i].Scale(device_scale_factor_);
+        copy_rects[i].ScaleUnsafe(device_scale_factor_);
     SkRect dstrect = SkRect::MakeXYWH(
         SkIntToScalar(pixel_copy_dst_rect.x()),
         SkIntToScalar(pixel_copy_dst_rect.y()),
@@ -128,7 +128,7 @@ void BackingStoreAura::PaintToBackingStore(
 void BackingStoreAura::ScrollBackingStore(int dx, int dy,
                                           const gfx::Rect& clip_rect,
                                           const gfx::Size& view_size) {
-  gfx::Rect pixel_rect = clip_rect.Scale(device_scale_factor_);
+  gfx::Rect pixel_rect = clip_rect.ScaleUnsafe(device_scale_factor_);
   int pixel_dx = dx * device_scale_factor_;
   int pixel_dy = dy * device_scale_factor_;