Split DumpPixelsAsync in pixel_dump.h into more granular functions.

content/shell/test_runner/test_runner.h

Index: content/shell/test_runner/test_runner.h
diff --git a/content/shell/test_runner/test_runner.h b/content/shell/test_runner/test_runner.h
index 02d978fc8253e2ae3b55cd0a0a9f90614af3c380..739d6de9c4f4b6e16609d5f17d42caea9ae0e9e8 100644
--- a/content/shell/test_runner/test_runner.h
+++ b/content/shell/test_runner/test_runner.h
@@ -93,8 +93,8 @@ class TestRunner : public WebTestRunner {
   bool IsRecursiveLayoutDumpRequested() override;
   std::string DumpLayout(blink::WebLocalFrame* frame) override;
   void DumpPixelsAsync(
-      blink::WebView* web_view,
-      const base::Callback<void(const SkBitmap&)>& callback) override;
+      blink::WebLocalFrame* frame,
+      base::OnceCallback<void(const SkBitmap&)> callback) override;
   void ReplicateLayoutTestRuntimeFlagsChanges(
       const base::DictionaryValue& changed_values) override;
   bool HasCustomTextDump(std::string* custom_text_dump) const override;