Remove PaintImage trace from KnownToBeOpaque in StyleFetchedImage

Remove obsolete PaintImage trace from StyleFetchedImage::KnownToBeOpaque
and StyleFetchedImageSet::KnownToBeOpaque. Trace was originally added in
late 2014 (in r186030) to the ImageResource::currentFrameKnownToBeOpaque
method as it, at the time, caused a forced decode for the image. That is
no longer the case yet the trace call has stubbornly survived unchanged.

R=pdr@chromium.org

Review-Url: https://codereview.chromium.org/2880573003
Cr-Commit-Position: refs/heads/master@{#471089}

third_party/WebKit/Source/core/style/StyleFetchedImage.cpp

@@ -130,9 +130,6 @@ PassRefPtr<Image> StyleFetchedImage::GetImage(
 
 bool StyleFetchedImage::KnownToBeOpaque(
     const LayoutObject& layout_object) const {
-  TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "PaintImage",
-               "data",
-               InspectorPaintImageEvent::Data(&layout_object, *image_.Get()));
   return image_->GetImage()->CurrentFrameKnownToBeOpaque(
       Image::kPreCacheMetadata);
 }

third_party/WebKit/Source/core/style/StyleFetchedImageSet.cpp

@@ -128,9 +128,6 @@ PassRefPtr<Image> StyleFetchedImageSet::GetImage(
 
 bool StyleFetchedImageSet::KnownToBeOpaque(
     const LayoutObject& layout_object) const {
-  TRACE_EVENT1(
-      TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "PaintImage", "data",
-      InspectorPaintImageEvent::Data(&layout_object, *best_fit_image_.Get()));
   return best_fit_image_->GetImage()->CurrentFrameKnownToBeOpaque(
       Image::kPreCacheMetadata);
 }