Add non-member non-mutating methods for common gfx::Rect operations.

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 5d1149a5f50466fb15d7466e55e929c5873d34ff..82d78d716aa63bd6990460c539eda9a1c4025fb0 100644
--- a/content/browser/renderer_host/backing_store_aura.cc
+++ b/content/browser/renderer_host/backing_store_aura.cc
@@ -91,9 +91,8 @@ void BackingStoreAura::PaintToBackingStore(
   if (bitmap_rect.IsEmpty())
     return;
 
-  gfx::RectF scaled_bitmap_rect = bitmap_rect;
-  scaled_bitmap_rect.Scale(scale_factor);
-  gfx::Rect pixel_bitmap_rect = gfx::ToEnclosedRect(scaled_bitmap_rect);
+  gfx::Rect pixel_bitmap_rect = gfx::ToEnclosedRect(
+      gfx::ScaleRect(bitmap_rect, scale_factor));
 
   const int width = pixel_bitmap_rect.width();
   const int height = pixel_bitmap_rect.height();
@@ -113,19 +112,16 @@ 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++) {
-    gfx::RectF scaled_copy_rect = copy_rects[i];
-    scaled_copy_rect.Scale(scale_factor);
-    const gfx::Rect pixel_copy_rect = gfx::ToEnclosingRect(scaled_copy_rect);
+    const gfx::Rect pixel_copy_rect = gfx::ToEnclosingRect(
+        gfx::ScaleRect(copy_rects[i], 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,
         pixel_copy_rect.width(),
         pixel_copy_rect.height());
 
-    gfx::RectF scaled_copy_dst_rect = copy_rects[i];
-    scaled_copy_dst_rect.Scale(device_scale_factor_);
-    const gfx::Rect pixel_copy_dst_rect =
-        gfx::ToEnclosingRect(scaled_copy_dst_rect);
+    const gfx::Rect pixel_copy_dst_rect = gfx::ToEnclosingRect(
+        gfx::ScaleRect(copy_rects[i], device_scale_factor_));
     SkRect dstrect = SkRect::MakeXYWH(
         SkIntToScalar(pixel_copy_dst_rect.x()),
         SkIntToScalar(pixel_copy_dst_rect.y()),
@@ -138,9 +134,8 @@ void BackingStoreAura::PaintToBackingStore(
 void BackingStoreAura::ScrollBackingStore(int dx, int dy,
                                           const gfx::Rect& clip_rect,
                                           const gfx::Size& view_size) {
-  gfx::RectF scaled_clip_rect = clip_rect;
-  scaled_clip_rect.Scale(device_scale_factor_);
-  gfx::Rect pixel_rect = gfx::ToEnclosingRect(scaled_clip_rect);
+  gfx::Rect pixel_rect = gfx::ToEnclosingRect(
+      gfx::ScaleRect(clip_rect, device_scale_factor_));
   int pixel_dx = dx * device_scale_factor_;
   int pixel_dy = dy * device_scale_factor_;