Revert "cc: Move canvas clear from picture to picture_pile_impl"

cc/resources/picture.cc

 // Copyright 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.
 
 #include "cc/resources/picture.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 149 matching lines @@
   SkCanvas* canvas = picture_->beginRecording(
       layer_rect_.width(),
       layer_rect_.height(),
       SkPicture::kUsePathBoundsForClip_RecordingFlag |
       SkPicture::kOptimizeForClippedPlayback_RecordingFlag);
 
   canvas->save();
   canvas->translate(SkFloatToScalar(-layer_rect_.x()),
                     SkFloatToScalar(-layer_rect_.y()));
 
-  SkPaint paint;
-  paint.setAntiAlias(false);
-  paint.setXfermodeMode(SkXfermode::kClear_Mode);
-  SkRect layer_skrect = SkRect::MakeXYWH(layer_rect_.x(),
-                                         layer_rect_.y(),
-                                         layer_rect_.width(),
-                                         layer_rect_.height());
-  canvas->clipRect(layer_skrect);
-  canvas->drawRect(layer_skrect, paint);
+  canvas->clipRect(RectToSkRect(layer_rect_));

[Tom Hudson, 2013/04/30 09:43:59]

Is this clip actually necessary, since we've created the canvas to be exactly
layer_rect size and offset?

[vmpstr, 2013/04/30 17:06:23]

I had it there initially, since I wasn't sure. But it makes that we don't need
it, I removed it.

 
   gfx::RectF opaque_layer_rect;
   base::TimeTicks begin_record_time;
   if (stats)
     begin_record_time = base::TimeTicks::Now();
   painter->PaintContents(canvas, layer_rect_, &opaque_layer_rect);
   if (stats) {
     stats->total_record_time += base::TimeTicks::Now() - begin_record_time;
     stats->total_pixels_recorded +=
         layer_rect_.width() * layer_rect_.height();
@@ skipping 224 matching lines @@
 
     // We found a non-empty list: store it and get the first pixel ref.
     current_pixel_refs_ = &iter->second;
     current_index_ = 0;
     break;
   }
   return *this;
 }
 
 }  // namespace cc