Add layer bounds to compositing_dislay_item

This patch adds an SkRect for bounds to compositing_display_item and
uses it for setting the canvas layer bounds. With this patch and the
associated blink-side patch [1] we pass the following additional
layout tests:
LayoutTests/svg/zoom/page/zoom-mask-with-percentages.svg
LayoutTests/svg/transforms/text-with-mask-with-svg-transform.svg
LayoutTests/svg/custom/absolute-sized-content-with-resources.xhtml
LayoutTests/svg/custom/mask-excessive-malloc.svg
LayoutTests/svg/batik/masking/maskRegions.svg

[1] https://codereview.chromium.org/960483002

Review URL: https://codereview.chromium.org/952123002

Cr-Commit-Position: refs/heads/master@{#318127}

cc/blink/web_display_item_list_impl.cc

@@ -98,12 +98,21 @@ void WebDisplayItemListImpl::appendEndTransparencyItem() {
   display_item_list_->AppendItem(cc::EndTransparencyDisplayItem::Create());
 }
 
+// TODO(pdr): Remove this once the blink-side callers have been removed.
 void WebDisplayItemListImpl::appendCompositingItem(
     float opacity,
     SkXfermode::Mode xfermode,
     SkColorFilter* color_filter) {
+  appendCompositingItem(opacity, xfermode, nullptr, color_filter);
+}
+
+void WebDisplayItemListImpl::appendCompositingItem(
+    float opacity,
+    SkXfermode::Mode xfermode,
+    SkRect* bounds,
+    SkColorFilter* color_filter) {
   display_item_list_->AppendItem(cc::CompositingDisplayItem::Create(
-      opacity, xfermode, skia::SharePtr(color_filter)));
+      opacity, xfermode, bounds, skia::SharePtr(color_filter)));
 }
 
 void WebDisplayItemListImpl::appendEndCompositingItem() {

cc/blink/web_display_item_list_impl.h

@@ -50,9 +50,14 @@ class WebDisplayItemListImpl : public blink::WebDisplayItemList {
   virtual void appendTransparencyItem(float opacity,
                                       blink::WebBlendMode blend_mode);
   virtual void appendEndTransparencyItem();
+  // TODO(pdr): Remove this once the blink-side callers have been removed.
   virtual void appendCompositingItem(float opacity,
                                      SkXfermode::Mode,
                                      SkColorFilter*);
+  virtual void appendCompositingItem(float opacity,
+                                     SkXfermode::Mode,
+                                     SkRect* bounds,
+                                     SkColorFilter*);
   virtual void appendEndCompositingItem();
   virtual void appendFilterItem(const blink::WebFilterOperations& filters,
                                 const blink::WebFloatRect& bounds);

cc/resources/compositing_display_item.cc

@@ -15,8 +15,14 @@ namespace cc {
 
 CompositingDisplayItem::CompositingDisplayItem(float opacity,
                                                SkXfermode::Mode xfermode,
+                                               SkRect* bounds,
                                                skia::RefPtr<SkColorFilter> cf)
-    : opacity_(opacity), xfermode_(xfermode), color_filter_(cf) {
+    : opacity_(opacity),
+      xfermode_(xfermode),
+      has_bounds_(!!bounds),
+      color_filter_(cf) {
+  if (bounds)
+    bounds_ = SkRect(*bounds);
 }
 
 CompositingDisplayItem::~CompositingDisplayItem() {
@@ -28,7 +34,7 @@ void CompositingDisplayItem::Raster(SkCanvas* canvas,
   paint.setXfermodeMode(xfermode_);
   paint.setAlpha(opacity_ * 255);
   paint.setColorFilter(color_filter_.get());
-  canvas->saveLayer(NULL, &paint);
+  canvas->saveLayer(has_bounds_ ? &bounds_ : nullptr, &paint);
 }
 
 bool CompositingDisplayItem::IsSuitableForGpuRasterization() const {
@@ -41,13 +47,19 @@ int CompositingDisplayItem::ApproximateOpCount() const {
 
 size_t CompositingDisplayItem::PictureMemoryUsage() const {
   // TODO(pdr): Include color_filter's memory here.
-  return sizeof(float) + sizeof(SkXfermode::Mode);
+  return sizeof(float) + sizeof(bool) + sizeof(SkRect) +
+         sizeof(SkXfermode::Mode);
 }
 
 void CompositingDisplayItem::AsValueInto(
     base::trace_event::TracedValue* array) const {
   array->AppendString(base::StringPrintf(
       "CompositingDisplayItem opacity: %f, xfermode: %d", opacity_, xfermode_));
+  if (has_bounds_)
+    array->AppendString(base::StringPrintf(
+        ", bounds: [%f, %f, %f, %f]", static_cast<float>(bounds_.x()),
+        static_cast<float>(bounds_.y()), static_cast<float>(bounds_.width()),
+        static_cast<float>(bounds_.height())));
 }
 
 EndCompositingDisplayItem::EndCompositingDisplayItem() {

cc/resources/compositing_display_item.h

@@ -10,6 +10,7 @@
 #include "cc/resources/display_item.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
+#include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/gfx/geometry/rect_f.h"
 
@@ -25,9 +26,10 @@ class CC_EXPORT CompositingDisplayItem : public DisplayItem {
   static scoped_ptr<CompositingDisplayItem> Create(
       float opacity,
       SkXfermode::Mode xfermode,
+      SkRect* bounds,
       skia::RefPtr<SkColorFilter> color_filter) {
     return make_scoped_ptr(
-        new CompositingDisplayItem(opacity, xfermode, color_filter));
+        new CompositingDisplayItem(opacity, xfermode, bounds, color_filter));
   }
 
   void Raster(SkCanvas* canvas, SkDrawPictureCallback* callback) const override;
@@ -40,11 +42,14 @@ class CC_EXPORT CompositingDisplayItem : public DisplayItem {
  protected:
   CompositingDisplayItem(float opacity,
                          SkXfermode::Mode,
+                         SkRect* bounds,
                          skia::RefPtr<SkColorFilter>);
 
  private:
   float opacity_;
   SkXfermode::Mode xfermode_;
+  bool has_bounds_;
+  SkRect bounds_;
   skia::RefPtr<SkColorFilter> color_filter_;
 };