Add fixed raster scale use counter histograms.

content/renderer/gpu/render_widget_compositor_delegate.h

Index: content/renderer/gpu/render_widget_compositor_delegate.h
diff --git a/content/renderer/gpu/render_widget_compositor_delegate.h b/content/renderer/gpu/render_widget_compositor_delegate.h
index e31e19e26b56ce8e3178ebd40750049d902e5e58..c688ef9fdadd9ee1403485990f6b78bf2c57ea05 100644
--- a/content/renderer/gpu/render_widget_compositor_delegate.h
+++ b/content/renderer/gpu/render_widget_compositor_delegate.h
@@ -83,6 +83,12 @@ class CONTENT_EXPORT RenderWidgetCompositorDelegate {
   // perform actual painting work.
   virtual void WillBeginCompositorFrame() = 0;
 
+  // Indicates that the last commit would have a blurry content or potential
+  // performance regression in a fixed raster scale layer.
+  virtual void ReportFixedRasterScaleUseCounters(
+      bool has_blurry_content,
+      bool has_potential_performance_regression) = 0;
+
  protected:
   virtual ~RenderWidgetCompositorDelegate() {}
 };