Adding test to verify that Canvas2DLayerBridge flushes only when required

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h

Index: third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
diff --git a/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h b/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
index 53b26f1a3f3e144d8912099d85d16e1c79775293..0ba1285a88569ec4d77aafd675ef5b4ac8fe6395 100644
--- a/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
+++ b/third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.h
@@ -144,6 +144,8 @@ class PLATFORM_EXPORT Canvas2DLayerBridge
   sk_sp<SkColorSpace> colorSpace() const { return m_colorSpace; }
   SkColorType colorType() const { return m_colorType; }
 
+  bool hasRecordedDrawCommands() { return m_haveRecordedDrawCommands; }
+
   sk_sp<SkImage> newImageSnapshot(AccelerationHint, SnapshotReason);
 
   // The values of the enum entries must not change because they are used for