cc: Refactor SkipImageCanvas and create it during playback.

cc/playback/display_list_raster_source.cc

Index: cc/playback/display_list_raster_source.cc
diff --git a/cc/playback/display_list_raster_source.cc b/cc/playback/display_list_raster_source.cc
index fe707ec978e2ee6d99b63cb8435c916b5565c4ff..a6d2c841b6a3b6bf7db3c554a1b3979c5a6d6f5e 100644
--- a/cc/playback/display_list_raster_source.cc
+++ b/cc/playback/display_list_raster_source.cc
@@ -14,6 +14,7 @@
 #include "cc/debug/debug_colors.h"
 #include "cc/playback/display_item_list.h"
 #include "cc/playback/image_hijack_canvas.h"
+#include "cc/playback/skip_image_canvas.h"
 #include "skia/ext/analysis_canvas.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
@@ -96,11 +97,15 @@ DisplayListRasterSource::~DisplayListRasterSource() {
 void DisplayListRasterSource::PlaybackToSharedCanvas(
     SkCanvas* raster_canvas,
     const gfx::Rect& canvas_rect,
-    float contents_scale) const {
+    float contents_scale,
+    bool include_images) const {
   // TODO(vmpstr): This can be improved by plumbing whether the tile itself has
   // discardable images. This way we would only pay for the hijack canvas if the

[ericrk, 2016/03/14 21:40:13]

nit: comment probably applies to both cases - not just discardable - if a tile
has no images, we don't want to pay the cost of the SkipImagesCanvas?

   // tile actually needed it.
-  if (display_list_->MayHaveDiscardableImages()) {
+  if (!include_images) {
+    SkipImageCanvas canvas(raster_canvas);
+    RasterCommon(&canvas, nullptr, canvas_rect, canvas_rect, contents_scale);
+  } else if (display_list_->MayHaveDiscardableImages()) {
     const SkImageInfo& info = raster_canvas->imageInfo();
     ImageHijackCanvas canvas(info.width(), info.height(),
                              image_decode_controller_);
@@ -123,11 +128,16 @@ void DisplayListRasterSource::PlaybackToCanvas(
     SkCanvas* raster_canvas,
     const gfx::Rect& canvas_bitmap_rect,
     const gfx::Rect& canvas_playback_rect,
-    float contents_scale) const {
+    float contents_scale,
+    bool include_images) const {
   PrepareForPlaybackToCanvas(raster_canvas, canvas_bitmap_rect,
                              canvas_playback_rect, contents_scale);
 
-  if (display_list_->MayHaveDiscardableImages()) {
+  if (!include_images) {
+    SkipImageCanvas canvas(raster_canvas);
+    RasterCommon(&canvas, nullptr, canvas_bitmap_rect, canvas_playback_rect,
+                 contents_scale);
+  } else if (display_list_->MayHaveDiscardableImages()) {
     const SkImageInfo& info = raster_canvas->imageInfo();
     ImageHijackCanvas canvas(info.width(), info.height(),
                              image_decode_controller_);