cc: Update discardable image metadata generation to get PaintImages.

cc/paint/paint_op_buffer.cc

Index: cc/paint/paint_op_buffer.cc
diff --git a/cc/paint/paint_op_buffer.cc b/cc/paint/paint_op_buffer.cc
index 0a1897852f3e51ca3d91b67460b2d6e84dace61a..2617ba93047d318f49d364f1f23db13dbf049e89 100644
--- a/cc/paint/paint_op_buffer.cc
+++ b/cc/paint/paint_op_buffer.cc
@@ -4,11 +4,37 @@
 
 #include "cc/paint/paint_op_buffer.h"
 
+#include "cc/paint/discardable_image_store.h"
 #include "cc/paint/display_item_list.h"
 #include "cc/paint/paint_record.h"
 #include "third_party/skia/include/core/SkAnnotation.h"
 
 namespace cc {
+namespace {
+// Currently this function only handles extracting images from SkImageShaders
+// embedded in SkPaints. Other embedded image cases, such as SkPictures,
+// are not yet handled.
+void AddImageFromFlags(DiscardableImageStore* image_store,

[vmpstr, 2017/04/27 16:28:54]

It feels like this should be a member on DiscardableImageStore

[Khushal, 2017/04/27 22:06:02]

Done.

+                       const SkRect& rect,
+                       const PaintFlags& flags) {
+  SkShader* shader = flags.getShader();
+  if (shader) {
+    SkMatrix matrix;
+    SkShader::TileMode xy[2];
+    SkImage* image = shader->isAImage(&matrix, xy);
+    if (image) {
+      PaintImage paint_image(sk_ref_sp(image),
+                             PaintImage::AnimationType::UNKNOWN,
+                             PaintImage::CompletionState::UNKNOWN);
+      // TODO(ericrk): Handle cases where we only need a sub-rect from the
+      // image. crbug.com/671821
+      image_store->AddImage(paint_image, SkRect::MakeFromIRect(image->bounds()),
+                            rect, &matrix, flags);
+    }
+  }
+}
+
+}  // namespace
 
 #define TYPES(M)           \
   M(AnnotateOp)            \
@@ -574,6 +600,97 @@ void PaintOpBuffer::playback(SkCanvas* canvas,
   }
 }
 
+void PaintOpBuffer::GatherDiscardableImages(

[vmpstr, 2017/04/27 16:28:54]

hmmmmm. Have you considered flipping |this| and |image_store|? Ie,
image_store->GatherDiscardableImages(paint_op_buffer) and implementing this in
there? Is there something that precludes this?

[Khushal, 2017/04/27 22:06:02]

Done.

+    DiscardableImageStore* image_store) const {
+  if (!has_discardable_images_)
+    return;
+
+  SkCanvas* canvas = image_store->NoDrawCanvas();
+  SkMatrix original = canvas->getTotalMatrix();
+  canvas->save();
+  for (auto* op : Iterator(this)) {

[vmpstr, 2017/04/27 16:28:54]

I was hoping to implement a smarter iterator for this that can skip save/restore
blocks if there are no images. Do you think that's a follow up work?

[Khushal, 2017/04/27 22:06:02]

Yeah. Its worth looking at in a follow up patch.

+    if (op->IsDrawOp()) {
+      switch (op->GetType()) {
+        case PaintOpType::DrawArc: {
+          auto* arc_op = static_cast<DrawArcOp*>(op);
+          AddImageFromFlags(image_store, arc_op->oval, arc_op->flags);
+        } break;
+        case PaintOpType::DrawCircle: {
+          auto* circle_op = static_cast<DrawCircleOp*>(op);
+          SkRect rect =
+              SkRect::MakeXYWH(circle_op->cx - circle_op->radius,
+                               circle_op->cy - circle_op->radius,
+                               2 * circle_op->radius, 2 * circle_op->radius);
+          AddImageFromFlags(image_store, rect, circle_op->flags);
+        } break;
+        case PaintOpType::DrawDisplayItemList: {
+          auto* list_op = static_cast<DrawDisplayItemListOp*>(op);
+          list_op->list->GatherDiscardableImages(image_store);
+        } break;
+        case PaintOpType::DrawImage: {
+          auto* image_op = static_cast<DrawImageOp*>(op);
+          const SkImage* sk_image = image_op->image.sk_image().get();
+          image_store->AddImage(
+              image_op->image,
+              SkRect::MakeIWH(sk_image->width(), sk_image->height()),
+              SkRect::MakeXYWH(image_op->left, image_op->top, sk_image->width(),
+                               sk_image->height()),
+              nullptr, image_op->flags);
+        } break;
+        case PaintOpType::DrawImageRect: {
+          auto* image_rect_op = static_cast<DrawImageRectOp*>(op);
+          SkMatrix matrix;
+          matrix.setRectToRect(image_rect_op->src, image_rect_op->dst,
+                               SkMatrix::kFill_ScaleToFit);
+          image_store->AddImage(image_rect_op->image, image_rect_op->src,
+                                image_rect_op->dst, &matrix,
+                                image_rect_op->flags);
+        } break;
+        case PaintOpType::DrawIRect: {
+          auto* rect_op = static_cast<DrawIRectOp*>(op);
+          AddImageFromFlags(image_store, SkRect::Make(rect_op->rect),
+                            rect_op->flags);
+        } break;
+        case PaintOpType::DrawOval: {
+          auto* oval_op = static_cast<DrawOvalOp*>(op);
+          AddImageFromFlags(image_store, oval_op->oval, oval_op->flags);
+        } break;
+        case PaintOpType::DrawPath: {
+          auto* path_op = static_cast<DrawPathOp*>(op);
+          AddImageFromFlags(image_store, path_op->path.getBounds(),
+                            path_op->flags);
+        } break;
+        case PaintOpType::DrawRecord: {
+          auto* record_op = static_cast<DrawRecordOp*>(op);
+          record_op->record->GatherDiscardableImages(image_store);
+        } break;
+        case PaintOpType::DrawRect: {
+          auto* rect_op = static_cast<DrawRectOp*>(op);
+          AddImageFromFlags(image_store, rect_op->rect, rect_op->flags);
+        } break;
+        case PaintOpType::DrawRRect: {
+          auto* rect_op = static_cast<DrawRRectOp*>(op);
+          AddImageFromFlags(image_store, rect_op->rrect.rect(), rect_op->flags);
+        } break;
+        // TODO(khushalsagar): Check if we should be querying images from any of
+        // the following ops.
+        case PaintOpType::DrawPosText:
+        case PaintOpType::DrawLine:
+        case PaintOpType::DrawDRRect:
+        case PaintOpType::DrawText:
+        case PaintOpType::DrawTextBlob:
+        case PaintOpType::DrawColor:
+          break;
+        default:
+          NOTREACHED();
+      }
+    } else {
+      op->Raster(canvas, original);
+    }
+  }
+  canvas->restore();
+}
+
 void PaintOpBuffer::ShrinkToFit() {
   if (!used_ || used_ == reserved_)
     return;