Only allow subsequence caching for SVG documents, not inline SVG.

third_party/WebKit/Source/core/svg/graphics/SVGImageTest.cpp

Index: third_party/WebKit/Source/core/svg/graphics/SVGImageTest.cpp
diff --git a/third_party/WebKit/Source/core/svg/graphics/SVGImageTest.cpp b/third_party/WebKit/Source/core/svg/graphics/SVGImageTest.cpp
index 9c71221fac1a3d5aa5bb0af66424176cce78fdb3..b4516c15db83cf4bcb6f4decd8a14966a4864b35 100644
--- a/third_party/WebKit/Source/core/svg/graphics/SVGImageTest.cpp
+++ b/third_party/WebKit/Source/core/svg/graphics/SVGImageTest.cpp
@@ -4,6 +4,9 @@
 
 #include "core/svg/graphics/SVGImage.h"
 
+#include "core/frame/FrameView.h"
+#include "core/layout/LayoutView.h"
+#include "core/paint/PaintLayer.h"
 #include "core/svg/graphics/SVGImageChromeClient.h"
 #include "platform/SharedBuffer.h"
 #include "platform/Timer.h"
@@ -145,4 +148,16 @@ TEST_F(SVGImageTest, ResetAnimation) {
   EXPECT_TRUE(timer->IsActive());
 }
 
+TEST_F(SVGImageTest, SupportsSubsequenceCaching) {
+  const bool kShouldPause = true;
+  Load(kAnimatedDocument, kShouldPause);
+  PumpFrame();
+  LocalFrame* local_frame = ToLocalFrame(GetImage().GetPage()->MainFrame());
+  EXPECT_TRUE(local_frame->GetDocument()->IsSVGDocument());
+  LayoutObject* svg_root = local_frame->View()->GetLayoutView()->ChildAt(0);

[fs, 2017/05/17 11:14:45]

Nit: s/ChildAt(0)/FirstChild/ (ChildAt is quite the oddity, and we should
probably avoid adding new uses of it... even more so when they are this trivial)

[chrishtr, 2017/05/17 17:01:18]

Done.

+  EXPECT_TRUE(svg_root->IsSVGRoot());
+  EXPECT_TRUE(
+      ToLayoutBoxModelObject(svg_root)->Layer()->SupportsSubsequenceCaching());
+}
+
 }  // namespace blink